UC-N 


B    M    111    fl3fl 


AUTHORIZED   IRAN 


MEDICAL 


Florence  IT.    -.7ard 
I  lemorial 


SCHENK'S   THEORY 


THE 


DETERMINATION  OF  SEX 


BY 


DR.  LEOPOLD  SCHENK 

Professor  at  the  Imperial  and  Royal  University,  and  Director  of  th« 
Embryological  Institute  in  Vienna 


AUTHORIZED    TRANSLATION 


THE    WERNER    COMPANY 

CHICAGO          AKRON,  OHIO          NEW   YORK 
1898 


COPYRIGHTED,  1898, 

BY 
THE  WERNER  COMPANY 


Q  r  .iol 
S32, 
1893 


PREFACE 

THE  facts  observed  and  recorded  by  others 
assisted  me  to  advance  so  far  on  the  trodden 
path  that  I  made  an  effort  to  snatch  a  secret 
from  Nature. 

What  I  succeeded  in  obtaining,  though 
small,  induced  me  to  set  forth  in  the  follow- 
ing pages  the  perhaps  not  unimportant  re- 
sults. 

The  labor  was  long,  and  engaged  my  at- 
tention for  years.  And  yet,  amidst  my  con- 
tinuous labors  in  the  province  of  Embryology, 
it  remained  all  the  time  a  matter  of  second- 
ary importance,  my  principal  attention  being 
engaged  by  far  more  extensive  studies. 

My  desire  is  to  stimulate  others  to  wider 
observation.  May  the  facts  which  I  here  dis- 
iii 


71 


PREFACE 

cuss  prove  of  utility,  and  encourage  further 
studies  in  this  direction  with  the  assistance 
of  modern  science. 

If  we  are  not  in  a  position  to  control  the 
processes  of  Nature,  we  can  nevertheless 
exercise  over  them  a  more  or  less  effective 
influence,  so  as  to  obtain  such  results  as  are 
possible. 

Whatsoever  the  question  may  be  that  we 
propose  to  discuss,  it  is  sometimes  very  difficult 
to  reach  any  answer.  And  yet,  when  experi- 
ence and  diligence  have  helped  us  over  the 
difficulties,  we  succeed  at  last  in  reaching  the 
answer  desired.  The  difficulties  assume  much 
less  formidable  shapes  when  an  individual  is 
satisfied  with  shaking  his  head  and  regarding 
the  whole  affair  with  mistrust.  In  that  way 
the  inexperienced  and  lazy  are  at  once  able 
to  launch  their  views  without  further  trouble. 
They  believe  or  they  disbelieve;  and  they 
like  to  have  their  say.  Any  one  can  in  this 
way  easily  win  himself  a  place  amongst  those 

iv 


PREFACE 

who  have  written  on  a  topic.  The  man  who 
desires  to  obtain  a  lasting  place  takes  on  his 
shoulders  heavier  responsibilities. 

This  book  contains  but  a  portion  of  the 
vast  and  wide-reaching  literature  dealing  with 
the  subject  in  hand.  That  literature  extends 
back  to  the  date  of  man's  earliest  intellectual 
labors.  The  observations  that  have  been  re- 
corded by  others  are  here  followed  by  meth- 
ods of  investigation,  and  by  considerations 
which  may  serve  to  elucidate  the  facts.  In 
conclusion,  a  section  has  been  dedicated  to 
the  methods  which  I  recommend  for  the  ar- 
tificial influencing  of  sex.  Some  particular 
experiments  are  subjoined. 

May  my  little  book,  then,  go  out  into  the 
world  and  make  known  my  views,  which  are 
founded  exclusively  upon  facts. 


CHAPTER   I 

IN  sexually  differentiated  individuals,  the 
difference  of  sex  is  already  apparent  in  the 
embryonal  state  of  existence,  not  only  in  the 
exterior  form,  but  also  in  the  interior  cellular 
rudiments  which  subsequently  form  the  geni- 
tal organs.  In  both,  the  earliest  forms  are  of 
such  a  nature  that,  up  to  a  certain  period,  it 
is  impossible  for  investigations  conducted  with 
the  means  at  present  at  our  disposal  to  dis- 
cover any  distinction.  Soon,  however,  after 
this,  in  such  organisms  as  have  a  distinction 
of  sex,  elementary  male  and  female  forms  of 
the  organs  of  reproduction  can  be  recognized 
developing  themselves  in  the  embryo  out  of 
the  substratum  of  formative  elements.  Some 
of  these  remain  in  a  rudimentary  condition; 
others  attain  to  complete  development. 


SCHENJCS   THEORY 

These  processes  take  place  at  a  relatively 
early  period.  They  do  not  seem  to  make 
their  first  appearance,  as  phenomena  of  vital- 
ity, in  the  course  of  the  life -development  of 
the  cells  of  the  ovum.  But  it  is  not  improbable 
that,  from  the  very  outset,  the  ovule  has  a 
capacity  to  transfer  (during  the  process  of  seg- 
mentation) to  a  corresponding  cell-substance 
(out  of  which  the  generative  organs  will  be 
subsequently  developed)  the  force  contained 
in  the  ovule,  so  that  the  cell-substance  may 
afterwards  take  up  the  office  of  providing  for 
the  preservation  of  the  species.  The  cells  of 
the  ovum  derive  this  power  from  the  proto- 
plasma  of  the  ovum,  and  retain  it  in  a  rudi- 
mentary form  for  one  sex,  whilst  for  the 
other  they  possess  it  in  full  measure.  This 
energy  is  contained  in  the  ovule  itself  in  an 
unknown  condition.  In  it  lies  the  basis  of  the 
formation  and  development  of  the  future  sex. 
In  close  connection  with  this  property  of  the 
ovule,  lies  another  faculty,  included  in  the 
8 


THE   DETERMINATION  OF  SEX 

ovule,  namely,  that  the  other  different  ele- 
ments proceeding-  from  the  cell-body  of  the 
ovum,  starting  from  the  protoplasma  of  the 
ovum,  are  endowed  with  certain  vital  pecul- 
iarities, according  as  they  belong  to  the  fu- 
ture male,  or  female,  organisms. 

It  will  be  plain  from  this  that  the  germ  of 
the  future  sex  must  be  sought  in  the  first  cell- 
segmentation  of  an  ovum.  As  soon  as  some 
of  the  cells  derived  from  the  primary  pro- 
toplasm of  the  ovum  have  developed  them- 
selves into  genital  cells,  the  other  elements 
which  have  originated  from  the  same  ovum 
are  in  such  a  manner  conditioned  that,  in  the 
latter  stages  of  their  vitality,  they  adapt  them- 
selves, and,  in  short,  adapt  the  properties  in- 
herent in  all  the  cells,  to  the  sex  of  the 
individual.  According,  as  the  ovum  is  male 
or  female,  so  are  also  the  cells  which  origi- 
nate from  it  either  all  male  or  all  female. 

It  will  be  seen  that  not  only  do  different 
cells  for  the  different  sexes  develop  them- 

9 


SCHENK'S    THEORY 

selves  out  of  an  ovum,  but  that  also,  at  the 
same  time  with  these,  a  peculiarity  reveals 
itself  in  the  other  cells,  in  accordance  with 
which  the  sexually  different  organisms  exhibit 
a  difference  in  their  vital  capacities,  and  take 
also  different  forms.  The  distinction  between 
male  and  female  characteristics  appears  to 
be  determined  before  the  fecundation  of  the 
ovum.  The  formation  of  the  ova  in  the 
ovary,  and  their  further  development,  seem, 
however,  not  to  be  independent  of  external 
influences.  It  is  possible  that  upon  these  cir- 
cumstances depend  the  number  of  ova  con- 
tained in  the  ovary.  But,  apart  from  the 
question  of  quantity,  it  is  possible  that  many 
characteristics  might  so  affect  the  quality  of 
the  ovum,  as  to  exercise  an  influence  over  its 
capacity  for  fecundation.  We  may  here  men- 
tion an  experiment  which  was  made  with  the 
ova  of  a  rabbit,  from  which  it  was  quite  clear 
that  the  capacity  of  an  ovum  for  fecundation 
was  immediately  diminished  when  the  sur- 

10 


THE   DETERMINATION  OF  SEX 

rounding  elements  attached  to  the  ovule,  in 
consequence  of  the  density  of  their  investing 
substance,  offered  a  resistance  to  penetration 
by  the  spermatozoa.  (Schenk.)  The  penetra- 
tion of  a  spermatozoon  into  the  protoplasm 
of  the  ovum  becomes  possible  only  when,  in 
consequence  of  the  movements  of  the  sper- 
matozoon, the  cells  of  the  surface  of  the  ovum 
can  be  thrust  aside.  This  is  facilitated  when 
the  investing  substance  is  considerably  re- 
laxed, as  is  the  case  when  the  ovum  is  ripe. 
Other  circumstances,  also,  which  can  in  some 
cases  be  easily  detected,  may  prove  detri- 
mental to  fecundation  and  development.  In- 
deed, they  can  even  exercise  an  influence 
over  the  sex  which  is  to  be  developed  out  of 
the  ovum.  Bee-masters  (F.  Gerstung)  have 
frequently  shown  that  the  food  exercises  a 
striking  influence  upon  the  formation  of  sex 
in  the  ova.  (v.  Berlepsch.) 

All  evidence  goes  to  support  the  view  that 
such   external  influences  as  would  favorably 
ii 


SCHENK'S    THEORY 

affect  the  separate  sexual  individual  might 
also  promote  the  production  of  one  sex  or 
the  other.  In  Hensen's  valuable  work  on 
generation,  a  number  of  instances  are  ad- 
duced, gathered  from  various  authors,  which 
make  it  clear  that  the  nutrition  of  the  par- 
ents, apart  from  any  question  of  race,  is  ca- 
pable of  exercising  an  influence  upon  the  sex 
of  the  children.  (Ploss.)  In  plants  which 
produce  separate  male  and  female  blossoms 
(Lenkhart),  the  male  blossoms  are  more  nu- 
merous when  the  temperature  is  relatively 
high,  whilst  in  shaded  places  and  damp  soils 
a  greater  number  of  female  individuals  will 
be  observed. 


Facts  which  might  assist  to  explain  the 
origin  of  sex  have  been  sought  after  from 
very  early  times,  and  have  been  also  placed 
in  very  different  lights.  The  result  on  every 
occasion,  when  this  subject  has  been  dis- 
cussed, has  been  always  a  wide  difference  of 


12 


THE  DETERMINATION  OF  SEX 

opinion.  People  have,  in  consequence,  been 
induced  to  fall  back  upon  theories  of  differ- 
ent sorts,  theories  which  have  for  varying 
periods,  sometimes  long,  sometimes  short, 
been  accepted  as  of  some  assistance  towards 
a  scientific  explanation.  In  all  the  theories 
which  have  been  propounded,  the  sex  has 
been  regarded  as  already  determined  in  the 
ovum,  or  else  the  origin  of  the  sex  has  been 
assigned  to  some  early  stage  of  the  develop- 
ment. 

The  earliest  statements  extend  back  into 
the  ages  of  myth  and  fable,  in  consequence 
of  which  any  exact  comparison  of  them  is 
not  an  easy  task.  All  the  different  manuals 
which  deal  with  the  present  question  touch 
upon  these  early  views,  and  for  this  reason 
I  am  unwilling  entirely  to  ignore  them  here. 
I  shall,  accordingly,  select  a  few  of  the  more 
important  for  mention. 

The  reproductive  glands  of  the  two  sexes 
were  supposed  to  contain  generative  matter 

13 


SCHENK'S    THEORY 

distributed  in  such  a  way,  on  the  right  and 
left,  that  the  right  ovary  and  the  right  testi- 
cle contained  the  generative  secretions  for 
the  production  of  the  males,  and  the  left 
ovary  and  left  testicle  those  which  pro- 
duced females.  It  is  immediately  evident 
that,  according  to  this  theory,  it  was  impos- 
sible to  exercise  any  influence  over  the  sex 
of  the  future  individual.  This  primitive  the- 
ory is  ever  cropping  up  anew,  always  to  be 
again  rejected.  Of  various  other  theories  of 
the  same  kind,  only  those  deserve  any  atten- 
tion which  rest  upon  some  basis  of  fact.  Ac- 
cordingly, recourse  has  been  had  to  statistics, 
and  an  attempt  has  been  made  to  reach,  from 
the  figures  which  they  furnish,  some  certainty 
respecting  which  sex  was  the  more  numer- 
ous, and  what  should  be  concluded  to  be  the 
cause  of  the  greater  prevalence  of  the  one 
sex  or  the  other.  The  fact  was,  however, 
apparently  overlooked  that  the  available  sta- 
tistics, though  in  many  respects  of  the  highest 

14 


THE   DETERMINATION  OF  SEX 

scientific  value,  could  be  of  real  significance 
only  when  the  numbers  were  gathered  from 
widely  distributed  peoples  amongst  whom 
there  was  none  of  that  wandering  about  the 
world  which  characterizes  modern  society. 

I  am  at  the  same  time  unwilling  to  omit 
data,  resting  upon  numbers  which  have  been 
gathered  from  statistics,  and  are  not  without 
value  for  the  determination  of  many  impor- 
tant questions. 

Ploss  has  in  this  way  shown  that  in  favor- 
able years,  when  food  was  cheap,  the  births 
showed  an  excess  of  girls.  Under  unfavora- 
ble circumstances,  more  male  individuals  were 
born. 

A  comparison  of  statistics,  however,  soon 
led  to  another  theory,  which  culminated  in 
this  result,  that  in  all  countries  an  excess  of 
male  individuals  was  born. 

To  what  extent  this  relation  between  the 
numbers  of  the  sexes  can  be  maintained,  and 
may  serve  for  a  fixed  rule,  is  at  the  same 

15 


SCHENJTS   THEORY 

time  a  question  to  be  regarded  with  caution. 
An  unimpeachable  result  of  such  investi- 
gations is  rendered  more  unlikely  by  the 
fact  that  comparisons  of  numbers  lead  to 
a  conclusion  of  an  exactly  contrary  nature, 
making  the  feminine  sex  the  more  numer- 
ous. These  facts  at  once  suggest  that  we 
are  not  dealing  with  fixed  or  normally  recur- 
ring numerical  proportions,  which  would  re- 
peat themselves  at  each  numeration.  And  it 
is  also  possible  that  external  influences  may 
in  various  ways  affect  such  numerical  propor- 
tions. 

We  may  add  also  that,  in  investigations  of 
this  kind,  other  circumstances  should  be  taken 
into  consideration.  Thus,  in  the  case  of  en- 
demic or  epidemic  disease,  the  births  which 
furnish  the  statistics  fluctuate,  and  the  stabil- 
ity of  the  numbers,  in  consequence,  is  modi- 
fied by  these  exceptional  occurrences. 

The  numbers  (Oesterlen)  which  are  based 
upon  the  population  of  half  Europe,  are 

16 


THE   DETERMINATION  OF  SEX 

amongst   the    widest    of    statistical   data,    and 
furnish  information  of  the  highest  value. 

They  represent  59,350,000  births.  These 
showed  an  excess  of  male  births.  The  pro- 
portions were  106.3  boys  to  100  girls.  Of 
course,  these  numbers  refer  to  the  new-born, 
and  must  necessarily  be  very  much  altered 
by  the  age  of  puberty.  In  fact,  the  powerful 
influences  which  come  into  play  in  the  life 
after  birth  would  very  considerably  affect  the 
former  of  the  above  numbers.  This  is,  how- 
ever, a  matter  for  further  statistical  investi- 
gation, and  of  little  importance  in  our  present 
inquiry.  The  numbers  (Oesterlen)  are  in 
this  respect  very  remarkable:  the  average  of 
the  total  number  of  births  in  the  various 
states  corresponds  very  nearly  with  the  num- 
bers in  the  several  states,  or  at  least  shows 
no  difference  worthy  of  consideration.  In  the 
single  states,  the  proportion  of  boys  to  100 
girls  varied  from  105.2  to  107.2.  Thus  the 
proportion  of  the  number  of  male  individuals 
2  17 


SCHENK'S    THEORY 

born  to  the  number  of  females  very  nearly 
corresponded  with  the  proportion  shown  by 
the  total  of  all  countries  enumerated.  Statis- 
tics derived  from  the  genealogies  of  Court 
calendars  gave  (according  to  Kisch)  107.7  boys 
to  100  girls. 

I  am  prompted  here  to  quote  also  the  sta- 
tistical numbers  given  in  Hensen's  work, 
which  have  been  taken  from  Darwin's  ( De- 
scent of  Man.  >  Of  pigs,  rabbits,  and  pigeons, 
more  males  are  born  than  females.  For 
every  100  mares,  99.4  horses  are  born.  In 
the  case  of  greyhounds,  no  dogs  are  born 
for  every  100  bitches.  Of  horned  cattle  94.4 
males,  of  poultry  94.7  males  are  born  for 
every  100  females.  The  degree  of  accuracy 
and  the  limits  of  error  which  here  remain  un- 
defined, make  fluctuations  easily  perceptible. 
The  mistakes,  also,  which  may  be  made  in 
such  cases,  are  not  always  the  same. 

Statistics  have  been  in  many  other  ways 
called  in  to  assist  in  the  discussion  of  the 
18 


THE   DETERMINATION  OF  SEX 

question  before  us.  In  the  early  decades  of 
the  present  century  a  question  was  raised  — 
what  was  the  effect  upon  the  relative  num- 
ber of  births  of  male  or  female  individuals 
when  the  parents  were  of  like  or  unlike 
ages? 

Hof acker,  in  the  year  1828,  and  Sadler  (an 
Englishman),  in  the  year  1830,  attempted  to 
solve  this  problem,  and  found  adherents  for 
their  theories  based  upon  numerical  returns. 
But  the  Frenchman,  Girou  (Paris,  1838),  ap- 
peared as  an  opponent  of  their  views,  also 
supporting  his  opinions  by  numbers  obtained 
in  the  same  manner,  probably,  as  those  of 
Hofacker  and  Sadler. 

I  shall  not  here  reproduce  the  tables  which 
were  constructed  for  the  discussion  of  this 
question.  Any  one  who  occupies  himself 
with  these  questions  can  refer  to  the  re- 
spective technical  works,  and  I  shall  content 
myself  with  mentioning  some  of  the  results. 
If  the  man  is  older  than  the  woman,  more 

19 


SCHENK'S    THEORY 

boys  will  be  born.  According  to  Sadler,  the 
statistics  showed  even  121.4  boys  for  100  girls. 

If  both  the  parents  are  of  the  same  age, 
fewer  boys  than  girls  will  be  born.  Accord- 
ing to  Sadler,  in  this  case  for  every  100  girls 
only  94.8  boys  are  born.  But  if  the  woman  is 
older  than  the  man,  an  excess  of  girls  in  the 
family  is  the  result.  According  to  the  two 
above-mentioned  authors,  when  the  mother  is 
older  than  the  father  the  proportions  are  : 
86.5  boys  to  100  girls. 

Similar  numbers  collected  by  other  special- 
ists differ  not  inconsiderably  from  those  given 
by  Sadler.  Regarding  the  proportions  of 
male  and  female  births  as  affected  by  the 
respective  ages  of  the  parents,  Sadler's 
numbers  show  the  widest  differences  of  all. 
Breslau  and  Noirot  have  arrived  at  numer- 
ical results  so  different,  though  less  than 
Sadler's,  that  no  thoroughly  reliable  conclu- 
sions can  be  based  upon  them.  Wall  con- 
fesses himself  an  adherent  of  this  law,  and 


20 


THE   DETERMINATION  OF  SEX 

lays  down  the  principle  that  in  the  inter- 
course of  two  quite  young  parents  the  male 
sex  tends  to  predominate.  If,  on  the  con- 
trary, the  age  of  the  man  is  distinctly  greater 
than  that  of  the  woman,  he  insists  on  the 
excess  of  females  amongst  the  new-born. 
The  French  breeder  Girou  de  Buzareingues 
is  disposed  in  many  respects  to  support  the 
theory  of  the  influence  of  difference  of  age 
in  the  parents  upon  sex  of  offspring;  but, 
also,  on  the  strength  of  his  own  experiences 
in  breeding,  is  partially  opposed  to  it.  Ac- 
cording to  his  theory,  he  also  takes  into  con- 
sideration the  character,  the  food,  etc.,  of 
the  parents,  and  would  have  regard  to  their 
size  and  strength.  In  this  way  he  gave  his 
theory  a  much  wider  range.  He  mentions  a 
great  number  of  facts  which  he  observed  in 
the  human  subject.  He  outlines  the  expendi- 
ture of  force,  mental  and  physical,  entailed 
on  the  parents  by  their  occupation,  and  then 
sets  forth  ten  very  precise  particulars  from 

21 


SCHENK'S    THEORY 

which,  in  any  given  case,  the  sex  of  the  off- 
spring which  will  result  from  the  wedlock  in 
question  may  be  known.  The  following  cases 
from  Girou  may  be  mentioned.  A  vigorous 
man  married  a  corpulent,  melancholy,  elderly 
blonde.  Seven  daughters  were  the  result  of 
the  marriage,  all  of  them  resembling  their 
father  and  grandfather.  Many  similar  cases 
are  mentioned  by  Girou,  all  of  which  may  be 
found  of  interest  to  the  reader,  if  he  be  in- 
clined to  regard  preponderance  of  tempera- 
ment, or  physical  disposition  for  procreation 
of  the  species  as  important  factors.  Included 
in  his  repertoire  of  anecdotes  are  many  in- 
teresting and  piquant  details  respecting  the 
results  of  the  pairing  of  dissimilar  tempera- 
ments which  might  be  quoted,  were  it  not 
that  this  would  lead  us  too  far  from  our  sub- 
ject, and  also  be  of  no  service  in  the  present 
inquiry. 

Bidder  is  in  many  respects  inclined  to  give 
his  assent  to  the  theories  of  his  predecessors, 

22 


THE   DETERMINATION  OF  SEX 

and  states  that  women  who  bear  their  first 
child  between  the  ages  of  twenty  and  twenty- 
one  produce  more  girls  than  boys  (Diising). 
The  older  the  woman  is  at  the  time  of  her 
first  parturition,  the  greater  number  of  male 
births.  An  excess  of  male  births  will  occur 
in  the  case  of  those  who  first  give  birth  to 
children  between  the  ages  of  thirty  and  forty 
(Eckhardt).  Ahlfeld  insists  that  this  is  a 
universal  rule  in  the  case  of  women  who  be- 
come pregnant  in  later  years.  A  great  num- 
ber of  specialists  are  of  this  opinion,  and 
apply  the  data  afforded  by  statistics  to  sup- 
port it  in  different  ways. 

The  evidence  of  Stieda,  Berner,  and  Birelli, 
and  especially  that  of  Wilkens,  respecting  the 
domesticated  mammals,  leads,  however,  to  this 
conclusion,  that  the  theories  respecting  the 
relative  proportions  of  male  and  female  births 
set  forth  by  Sadler  and  Hofacker  must  either 
be  given  up  or  their  value  considerably  dis- 
counted. 

23 


SCHENK'S    THEORY 

Specialists  are  also  to  be  found  who,  in 
order  to  explain  this  theory,  have  availed 
themselves  of  Darwin's  law,  and  in  a  certain 
measure  the  results  admit  of  this  explanation. 

The  older  parent,  who  evidently  under  such 
normal  circumstances  as  might  be  anticipated 
has  a  shorter  time  to  live  than  the  younger 
individual,  his  consort,  naturally  in  the  strug- 
gle for  life,  makes  an  effort  for  the  preserva- 
tion of  his  sex.  Accordingly,  the  elderly  hus- 
band of  a  young  wife,  or,  vice  versd,  the  elderly 
wife  of  a  young  husband,  will  make  an  effort 
to  preserve  the  sex  which  is  first  threatened 
with  death,  but  which  may  at  least  be  re- 
placed by  a  majority  of  births. 

In  so  far  as  these  theories  are  mere  calcu- 
lations and  results  which  have  originated  from 
comparisons  of  numbers  (the  numbers  them- 
selves being  in  many  cases  of  no  practical 
value),  the  conclusions  reached  may  appear 
to  be  astonishing,  and  may  be  used  to  sup- 
port either  one  view  or  another,  or  to  con- 
24 


THE   DETERMINATION  OF  SEX 

tradict  them.  Only  one  fact  appears  to  be 
certainly  established,  that,  on  an  average, 
under  normal  circumstances,  the  number  of 
male  individuals  of  our  population  that  are 
born  exceeds  the  number  of  females.  The 
difference  amounts  to  a  small  and  variable 
number  per  cent.,  but  in  the  case  of  the 
new-born,  the  excess  is  on  the  side  of  the 
males.  (Siissmilch.) 


Thus  far  we  have  given  such  data  as  sta- 
tistics have  furnished.  These,  it  is  true,  be- 
long principally  to  past  epochs,  and  no  new 
results  of  this  sort  have  been  used  by  statis- 
ticians. But  it  would  be  equally  impossible 
to  deduce  from  new  statistics,  or  from  old,  or 
from  both  together,  any  law  of  nature  affect- 
ing the  question  before  us. 


I  shall  proceed  next  to  examine  the  further 
theories  on  this  subject  with  which  I  have 
become  acquainted  from  the  perusal  of  the 

25 


SCHENK'S    THEORY 

literature  treating  of  it.  With  some  of  the 
works  which  I  am  about  to  mention  I  am  ac- 
quainted at  first  hand.  Others  I  know  only 
from  quotations  found  in  various  technical 
publications.  I  have  not  attempted  to  ar- 
range my  materials  in  any  other  way. 

In  the  case  of  the  most  widely  different 
branches  of  natural  science,  and  whether  the 
author's  aim  be  descriptive  or  experimental, 
it  is  a  common  practice  to  commence  with  a 
glimpse  at  what  has  been  said  by  the  earliest 
writers.  I  shall  begin  in  the  same  way.  I 
shall,  however,  not  take  into  consideration 
what  has  been  at  various  times  mere  folk-lore, 
and  is  only  traditionally  known,  but  shall 
limit  myself  to  such  traditions  as  have  been 
preserved  in  writing.  I  have,  besides,  already 
spoken  above  of  suppositions  respecting  the 
origin  of  sex  which  appear  to  partake  of  the 
nature  of  myths.  To  these  it  was  impossi- 
ble to  attach  any  importance.  And  the  same 
must  be  said  of  other  views  which  belong  to 

26 


THE   DETERMINATION  OF  SEX 

the  epoch  of  the  Greek  or  Latin  writers  on 
natural  science,  and  are  so  strange  that  they 
can  be  scarcely  brought  into  any  agreement 
with  modern  knowledge. 

In  Floss's  work  ^Das  Weib  in  der  Natur 
und  Volkerkunde^  (Woman  in  Nature  and 
Popular  Tradition),  are  to  be  found  the  vari- 
ous speculations  of  different  races  respecting 
the  origin  of  sex.  Much  of  this  folk-lore  is 
of  a  distinctly  surprising  character,  and  cal- 
culated to  afford  the  reader  considerable 
amusement.  For  example,  in  Servia,  if  a 
man  has  a  stye  on  his  eyelid  he  comes  to 
the  conclusion  that  his  aunt  is  pregnant.  If 
the  stye  is  on  the  upper  eyelid,  the  child  will 
be  a  male,  if  on  the  lower,  a  female. 

Amongst  the  Asiatic  races  religious  cere- 
monies, prayers,  and  similiar  expedients  are 
considered  efficacious,  and  capable  of  influ- 
encing the  sex. 

What  question  is  there  of  the  present  day, 
respecting  which  we  can  consult  the  literature 

27 


SCffENJCS    THEORY 

of  the  ancients,  that  does  not  take  us  back 
to  the  writings  of  Hippocrates,  Aristotle,  or 
Galen,  or  to  those  of  the  old  authors  of  those 
oriental  races  whom  we  regard  as  the  earliest 
cultivated  peoples  ?  Hippocrates  held  that  to 
produce  a  male,  the  generative  material  must 
be  of  a  stronger  quality.  The  future  destiny 
of  the  male  rendered  it  necessary  that  it 
should  be  constructed  on  a  stouter  foundation. 
He  must  be  capable  of  a  stronger  develop- 
ment, and  must,  therefore,  be  a  product  of 
stronger  elements  alike  on  the  father's  and 
the  mother's  side.  A  second  hypothesis  was 
soon  added  to  this  primary  one,  but  without 
any  foundation  of  facts. 

According  to  Aristotle,  the  woman  supplied 
the  primary  material  for  the  development  of 
the  future  individual.  It  was  the  function 
of  the  man  to  give  the  impulse,  in  conse- 
quence of  which  the  future  individual  came 
into  being.  Next  followed  the  purely  myth- 
ical theory,  already  mentioned,  in  which 

28 


THE   DETERMINATION  OF  SEX 

Anaxagoras  believed.  The  much-sought-for 
origin  of  the  future  difference  of  sex  in  the 
various  individuals  was  assigned  to  the  right 
or  left  side  of  the  organism.  And  Galen  even 
concluded  that  the  right  side  of  the  body  was 
the  warmer,  and  the  left  the  colder,  further 
claiming  for  the  warmer  side  the  privilege 
of  producing  male  individuals. 


Various  notions  respecting  the  origin  of 
sex  have  been  also  accommodated  to  these 
primitive  theories  of  the  ancients,  without 
resting  upon  any  positive  foundation.  No 
evidence  exists  to  show  from  whom  they  ori- 
ginated, nor  how  they  were  disseminated. 
Nevertheless,  the  historical  connection  of  these 
speculations  justifies  a  reference  to  them,  and 
various  hypotheses  of  this  kind  will  be  found 
in  a  little  publication  of  Dr.  Heinrich  Janke's 
(Stuttgart,  1896).  The  older  literature  on  the 
subject  of  the  generation  of  the  sexes  has 

29 


SCHENK'S   THEORY 

been  collected  by  His.  (Archiv  fur  Anthropo- 
logie,  Vol.  IV.  V.)  In  ^Das  Weib  in  der  Na- 
tur  und  Volkerkunde^  (Leipzig),  Ploss  has  col- 
lected ample  information  concerning  both 
ancient  and  modern  ideas  on  this  subject 
amongst  the  different  races  of  mankind.  The 
procreative  elements,  furnished  by  the  male 
and  female  organs,  after  their  mixture,  com- 
pete with  each  other,  by  virtue  of  their  in- 
herent forces,  for  the  mastery.  In  this  con- 
flict, if  the  male  molecules  are  the  more 
numerous,  a  male  results.  On  the  contrary, 
if  the  female  molecules  are  more  numerous, 
the  result  is  a  female.  Nicholaus  Venette 
ascribes  the  difference  of  sex  to  the  earliest 
phases  of  the  life  of  the  ovule. 


The  following  aspect  of  the  origin  of  sex 
is  not  without  interest,  although  the  theory 
rests  on  somewhat  insufficient  foundations, 
and  is  applicable,  in  the  first  instance,  only 


THE   DETERMINATION    OF  SEX 

to  those  creatures  which  produce  but  a  single 
individual  at  a  birth.  Many  creatures,  and 
especially  certain  species  of  birds,  present 
this  phenomenon;  they  lay  in  a  single  month 
two  eggs.  Of  these,  one  is  male,  the  other 
female.  In  this  way  a  provision  is  made  for 
the  equal  increase,  in  each  respective  month, 
of  both  sexes.  In  the  case  of  man,  it  would, 
in  accordance  with  this,  be  anticipated  that 
naturally  an  equal  number  of  ova  of  either 
sex  would  be  produced  by  a  single  indi- 
vidual. 

This  would  lead  to  the  supposition  that,  in 
the  case  of  the  human  female,  in  one  month 
a  male  ovule  would  reach  its  perfect  develop- 
ment, and  in  the  next  month,  anterior  to  the 
occurrence  of  the  menses,  a  female  ovule. 
Thus  the  ovary  of  the  human  female  would 
contain  in  one  month  a  male  ovum  capable 
of  fecundation,  and  in  the  following  month 
a  similar  female  ovum.  After  a  woman  had 
once  given  birth  to  a  child  it  would  then  be 

31 


SCHENK'S    THEORY 

possible  to  form  a  correct  idea  of  the  dis- 
tribution of  the  ova  of  the  different  sexes. 
The  month  of  birth  and  the  sex  of  the  new- 
born child  would  be  known,  and  starting 
from  the  datum  that  it  would  be  the  turn  of 
the  ovum  of  the  next  month  to  develop  the 
opposite  sex,  it  would  be  possible  to  fix  the 
given  month  in  which  an  individual  of  the 
male  or  female  sex  should  be  developed. 
(Dupuys.) 

To  these  less  general  explanations  of  the 
origin  of  sex  belong  certain  very  startling 
theories  dealing  with  the  question  before  us. 
These  notions  are  set  forth  at  great  length 
in  theoretical  explanations  put  in  the  shape 
of  popular  expositions.  According  to  these 
views  a  single  cell  of  the  male  or  female 
reproductive  glands  is  regarded  as  a  sort  of 
complicated  compound  structure  that  might 
be  compared  to  a  spherical  world,  in  which 
thousands  of  primal  individuals  are  contained, 
from  whose  powerful  and  secret  activity 

32 


THE   DETERMINATION  OF  SEX 

results  the  formation  of  male  or  female  indi- 
viduals.    (Hinz.   Neusalz  am  Oder,   1897.) 


Another  very  common  opinion  is  that  the 
seasons  (Busing),  the  climate,  and  other  local 
circumstances,  have  an  effect  in  determining 
the  sex  of  the  embryo.  If  the  data  supplied 
by  Birelli,  Berner,  C.  F.  Vilson,  and  Felkin, 
and  many  other  authors,  be  taken  together, 
it  appears  that  the  different  zones  of  the 
earth's  surface  are  not  without  influence  in 
the  reproduction  of  one  sex  rather  than  the 
other.  More  boys  appear  to  be  born  in  the 
north;  in  the  warmer  south  more  girls. 

Felkin  and  Vilson  adduce  the  following  in- 
stance from  the  south  of  Egypt:  —  The  Wa- 
gandas,  a  warlike  race,  kill  the  men  and  the 
old  women  of  their  conquered  foes.  The 
children,  girls,  and  young  women  they  lead 
into  captivity.  On  one  occasion  480  of  the 
women  gave  birth  to  children  on  their  march. 

3  33 


SCHENK'S    THEORY 

Of  the  new-born  79  were  boys,  403  girls. 
This  incident  led  the  author  to  pay  further 
attention  to  the  subject  on  the  east  coast  of 
Africa  and  in  the  Soudan.  Everywhere  he 
found  the  anticipation  of  an  excess  of  girls 
supported  and  confirmed.  In  fact  his  in- 
vestigations of  the  phenomenon  led  him  to 
formulate  and  advocate  a  law  that  the  better 
nourished  and  superior  parent  tends  to  pro- 
duce the  opposite  sex. 

In  this  case  the  women  are  in  an  inferior 
position,  and  in  consequence  worse  nourished 
and  practically  exhausted.  Amongst  other 
neighboring  races,  where  they  live  peaceably 
and  domestically,  the  difference  between  the 
number  of  new-born  boys  and  girls  is  not  a 
very  great  one,  although  a  small  average  ap- 
pears in  favor  of  the  girls.  The  influence 
of  different  phases  of  the  moon  has  also 
been  taken  into  consideration,  and  has  been 
described  as  so  effective  that  some  have  even 
attempted  to  prognosticate  by  these  means 

34 


THE   DETERMINATION    OF  SEX 

the  sex  of  a  second  child  after  the  birth  of  a 
first.   (Lioy.) 

From  Vilson's  statement  that  the  sex  of 
the  worse-fed  parent  perpetuates  itself,  a  theory 
has  been  deduced  which  has  been  described 
as  cross-heredity  of  sex  (Gekreuzte  Geschlechts- 
vererbung).  In  accordance  with  this  theory  a 
prominent  phenomenon  would  be  that  the 
individual  parents  were  not  in  a  position  to 
propagate  their  own  sex,  but  were  yet  under 
certain  circumstances  capable  of  reproducing 
the  opposite  sex.  If  the  father  were  the 
stronger,  a  girl  would  result  from  the  next 
impregnation;  in  the  opposite  case,  a  boy. 
A  great  number  of  authors  of  renown,  most 
of  whom  are  mentioned  in  works  dealing 
with  these  questions,  are  supporters  of  this 
theory. 

We  have  already  mentioned  that  there  are 
some  who  regard  the  act  of  generation  as  a 

35 


SCHENK'S    THEORY 

conflict  in  consequence  of  which  the  sex  of 
the  elder  parent,  whether  father  or  mother, 
will  be  reproduced,  so  that  the  sex  in  ques- 
tion may  maintain  its  position.  Similarly,  in 
the  case  of  the  so-called  cross-heredity  of  sex 
there  seems  to  be  a  conflict  for  the  preser- 
vation of  the  opposite  sex.  What  conception 
we  are  to  form  of  this  conflict  seems  a  diffi- 
cult question.  Any  measure  of  the  greater 
or  less  excitability  of  the  centers  during  the 
act  of  generation  (which  might  be  determined 
in  the  case  of  animals)  is  not  easily  to  be 
reached  with  any  degree  of  probable  correct- 
ness; and  how  much  less  any  numerical  in- 
dex which  would  express  the  differences  of 
excitability,  of  strength,  and  so  forth,  which 
might  be  developed  during  the  conflict  of 
the  opposite  sexes.  The  theory  of  the  cross- 
heredity  of  sex  rests  upon  the  phenomenon 
that  those  female  animals  which  are  impreg- 
nated by  sexually  inferior  and  older  males, 
whose  capacity  for  reproduction  must  be  con- 
36 


THE  DETERMINATION  OF  SEX 

sidered   as   inferior    to   that    of    the    females, 
produce  more  male  than  female  individuals. 


When  a  queen -bee  lays  male  eggs,  it  is  often 
asserted  that  these  are  not  yet  fecundated. 
It  is  only  after  they  have  been  impregnated 
by  the  male  that  the  female  individuals  ap- 
pear. That  is  to  say,  after  the  male  influence 
has  had  its  effect,  the  causes  which  lead  to 
the  development  of  the  female  make  them- 
selves apparent,  in  accordance  with  the  theory 
of  the  cross-heredity  of  sex.  Previously,  this 
influence  was  wanting,  and,  in  consequence, 
only  male  individuals  resulted  from  the  eggs. 

From  the  unfructified  eggs  of  Daphnia 
(water-flee)  many  individuals  are  at  once  de- 
veloped, and  in  numbers  so  great  as  to  be 
surprising.  According  to  Heincke,  female 
individuals  can  be  developed  from  eggs  which 
have  not  been  fructified,  but  have  been  well 
nourished. 

37 


SCHENK'S    THEORY 

Dr.  Clarke,  a  medical  man  of  Detroit,  is  of 
opinion  that  in  the  commixture  of  the  ele- 
ments, which  serve  as  the  basis  of  the  future 
individual,  some  external  force  is  also  em- 
bodied. Then  the  situation  would  be  some- 
thing like  this:  there  are  two  elemental 
forms,  which,  in  impregnation,  are  brought 
near  each  other,  and  their  union  actually  ef- 
fected; of  these  the  female  ovum  has  the 
function  of  occasioning  a  male  offspring,  and 
the  male  element  that  of  occasioning  a  female. 
In  this  act  a  conflict  is  supposed  to  take  place, 
in  which  each  sex  strives  for  the  production 
of  the  opposite  sex.  But  here  there  would 
be  also  an  expenditure  of  force  on  behalf  of 
its  own  sex.  This  appears  to  be  a  labor  of 
love  on  the  part  of  the  sexually  more  ardent 
consort,  to  which  he  or  she  finds  himself  or 
herself  prompted  by  nature  for  the  sake  of 
the  weaker  female  or  male  sex,  but  at  the 
same  time  without  any  conscious  volition  of 
accomplishing  an  expenditure  of  power  or 

38 


THE   DETERMINATION  OF  SEX 

energy  in  this  (reflex)  act.  Richarz  affirms 
that  it  is  the  function  of  the  man  to  produce 
a  higher  degree  of  organization  during  the 
development  in  the  germ.  But  if  the  pro- 
ductive force  of  the  mother  is  more  energetic, 
and  exerts  a  greater  influence,  the  result  is 
a  boy.  When,  on  the  contrary,  the  genera- 
tive force  excited  in  the  mother  by  success- 
ful fecundation  is  weaker,  the  fecundated 
germ  does  not  attain  the  masculine  sex. 

Cases  from  married  life  are  mentioned  by 
different  authors  in  which  the  husband,  partly 
in  consequence  of  sexual  debility,  occasioned 
by  repeated  seminal  emissions  on  previous 
occasions,  partly  in  consequence  of  advanced 
age,  and  besides,  also,  through  spermatic  se- 
cretion (Samensecretiori),  was  scarcely  capa- 
ble of  performing  his  conjugal  duties,  never- 
theless, pregnancy  ensued,  which  after  nine 
months  resulted  in  the  birth  of  a  boy.  In 
these  cases  the  mother  would  have  de- 
cided the  sex  of  the  child.  But  one  is  more 

39 


SCHENK'S    THEORY 

inclined  to  explain  the  origin  and  develop- 
ment of  a  boy  in  these  cases  by  the  law  of 
cross-heredity  of  sex.  It  may  certainly  be 
concluded  from  these  cases  that  a  man,  from 
whom  it  might  have  been  supposed  that  no 
procreative  substance  was  to  be  had,  although 
he  can  be  reckoned  amongst  the  patriarchs  of 
his  species,  may  yet  sometimes  be  able  to 
boast  that  he  has  left  male  offspring  to  be 
his  direct  heir. 

On  the  other  hand,  Guttceit  relates  that  a 
man,  during  the  period  anterior  to  his  having 
a  mistress,  and  whilst  he  was  entirely  at  the 
service  of  his  wife,  begoc  only  daughters. 
When,  however,  he  limited  the  time  which 
he  spent  with  his  wife  by  devoting  a  part  to 
a  mistress,  his  wife  presented  him  with  male 
offspring.  This  is  a  case  which  might  be  ex- 
plained by  the  law  of  cross-heredity  of  sex. 

Serious  surgical  interference  with  the  fe- 
male certainly  has  an  effect  upon  fecunda- 
tion. At  least,  pregnancy  appears  to  be 

40 


THE   DETERMINATION  OF  SEX 

postponed  after  the  more  difficult  operations. 
If,  however,  impregnation  takes  place,  either 
male  or  female  offspring  may  be  anticipated. 
This  contradicts  the  theory  of  cross-heredity 
of  sex,  according  to  which  only  individuals 
of  one  sex  should  appear,  if  one  ovary  has 
been  removed. 

Facts  which  have  been  brought  to  light  by 
experiments  with  animals,  and  by  observation 
in  the  human  subject,  tend  to  give  the  theory 
of  cross-heredity  of  sex  a  higher  value.  But 
under  the  same  circumstances,  other  phe- 
nomena present  themselves  to  observation 
which  appear  to  render  some  of  the  postu- 
lates of  this  theory  untenable.  Various  dis- 
eases which  are  diagnosed  by  medical  men 
as  organic  disorders,  but  which  do  not  in- 
terfere with  the  power  of  reproduction,  are 
apparently  without  influence  on  the  sex  of 
the  offspring,  and  also  without  influence 
upon  a  striking  prevalence  of  one  or  the 
other  sex. 

41 


SCHENK'S    THEORY 

Richarz  assigns  all  the  power  to  the  fecun- 
dated female  individual.  He  thus  raises  the 
culminating  point  of  the  female  power  of 
reproduction  to  a  height  above  that  which 
other  specialists  will  allow.  In  this  he  is  in 
complete  disagreement  with  Roth,  to  whom 
he  is  also  opposed  in  other  directions.  Within 
certain  individual  limits  (amongst  which  is 
not  to  be  included  a  diminution  of  capacity 
in  consequence  of  the  necessary  periodical 
functional  impulses),  the  female  organism  dis- 
charges its  functions  the  more  frequently  and 
the  more  perfectly  the  less  often  it  is  called 
into  operation,  and,  e  contra,  the  less  fre- 
quently and  the  less  perfectly  the  more  often 
it  is  called  into  operation.  According  to  Ver- 
nich,  very  long  intervals  between  successive 
pregnancies  disturb  the  progressive  increase 
in  the  weight  of  the  children  less  than  very 
short  ones. 

One  may,  without  being  afraid  of  making 
any  great  mistake,  at  any  rate  in  the  case  of 

42 


THE   DETERMINATION  OF  SEX 

women  who  bear  many  children,  make  the 
same  assertion  respecting  the  constantly  in- 
creasing probability  of  male  offspring,  as  re- 
specting the  increase  of  weight. 

The  beneficial  effect  of  a  fairly  long  fallow 
season  upon  these  periodically  acting  organs 
is  revealed  in  this  way  among  others,  that, 
often  enough,  in  consequence  of  prolonged 
rest  and  recovery  of  strength,  the  female  gen- 
erative organs,  after  frequent  still  births,  be- 
came capable  of  producing  healthy  children. 
(Richarz.) 

The  fundamental  law  of  crossing  is  sup- 
ported by  this  author  in  every  direction.  He 
recommends  it  as  revivifying  the  blood  and 
tissues,  in  order  to  combat  the  evil  effects 
of  inbreeding,  the  exhaustion  of  normal  and 
healthy  conditions,  and  as  a  preventative 
against  the  appearance  of  degeneration  and 
decay.  A  similar  relation  between  the  sexes 
exists  in  their  functions  for  the  continuation 
of  the  species. 

43 


SCHENK'S    THEORY 

If  an  attempt  be  made  (Richarz)  to  explain 
the  different  facts  observed,  in  accordance 
with  the  theory  in  question,  no  insuperable 
contradictions  will  be  met  with.  The  general 
excess  of  male  births,  their  corresponding  in- 
crease during  the  loss  of  many  men  in  war 
(a  loss  of  distinctly  stronger  men),  the  high 
proportion  of  male  births  in  the  case  of 
mothers  who  produce  their  first-born  at  a 
comparatively  late  age,  the  same  high  pro- 
portion where  polygamy  prevails,  and,  fur- 
ther, the  diminution  of  male  births  in  the 
case  of  unmarried  mothers,  which  should 
not  be  overlooked, —  all  these  phenomena  are 
declared  to  be  in  accord  with  Richarz's 
views. 

We  will  proceed  here  to  give  a  brief  sketch 
of  Richarz's  opinion.  Ribot  powerfully  sup- 
ports it  in  every  particular  from  his  own 
experience  and  from  historical  data.  The 
primary  impulse  upon  which  the  whole  proc- 
ess of  generation  depends  lies  in  the  organs 

44 


THE   DETERMINATION  OF  SEX 

of  the  mother.  Here  lies  also  the  substratum 
in  which  is,  as  it  were,  the  center  of  gravity 
of  the  special  generative  process. 

The  function  of  the  male  sex  is  to  evoke 
from  the  feminine  substratum  an  organism,  or, 
more  strictly  speaking,  to  occasion  a  change 
in  the  germ.  If  the  mother's  generative  ca- 
pacity reaches  the  highest  point  the  result  is 
a  boy,  who  in  external  appearance  resembles 
his  mother. 

If,  however,  it  happens  that  the  forces 
which  act  in  the  mother  are  inferipr  to  those 
of  the  father,  the  infant  will  be  a  female. 
She  will  resemble  her  father,  and  will  also 
inherit  her  father's  temperament.  Sex  is 
not  a  transmissible  attribute  inherited  di- 
rectly from  the  parents.  Personal  appearance 
and  other  characteristics  will  on  the  whole 
correspond  rather  more  with  one  of  the  par- 
ents than  with  the  other.  Yet  in  every  case 
the  influence  of  the  other  parent  will  make 
itself  felt,  and  will  in  many  respects  exercise 

45 


SCHENK'S    THEORY 

a  modifying  influence  over  external  appear- 
ance and  other  characteristics. 

These  views  have  been  attacked  by  Roth, 
who  declares  himself  against  Richarz's  hy- 
potheses. His  objections  are  contained  in  a 
work  entitled  (The  Phenomena  of  Heredity  > 
(Ueber  die  That  sac  hen  der  Vererbung).  He 
directly  attacks  the  theory  of  cross-heredity 
of  sex,  and  according  to  his  theory  claims 
for  each  parent  an  equal  share  in  the  forma- 
tion of  the  future  individual,  at  least  in  the 
earliest  stages.  Fecundation,  according  to 
Roth,  would  at  once  be  effective  in  deter- 
mining the  sex  of  the  future  individual. 

We  shall  have  occasion  hereafter  to  speak 
of  the  observations  which  Mayerhofer  has 
made  upon  the  origin  of  sex.  Here  we 
shall  mention  only  a  single  fact.  This  is  a 
result  of  his  experiments  with  animals,  and 
seems  to  have  a  relation  to  the  theory  of 
cross-heredity  of  sex. 

Ewes  impregnated  by  a  powerful  ram  bear 

46 


THE   DETERMINATION  OF  SEX 

more  males  than  females,  so  long  as  the  ram 
is  in  possession  of  his  full  forces.  After  a 
time  the  ram  has  to  perform  his  functions 
repeatedly  during  a  few  days,  as  great  num- 
bers of  the  ewes  are  rutting.  The  fatigued 
or  exhausted  ram  then  begets  only  females. 
Next  the  number  of  rutting  ewes  dimin- 
ishes. The  ram  gradually  recovers  his 
strength.  Whilst  constantly  employing  it 
with  the  remaining  rutting  ewes  he  again 
begets  male  individuals.  Now,  according  to 
the  rule  of  cross-heredity  of  sex,  the  number 
of -females  ought  to  be  greatest  at  the  outset, 
because  we  here  have  a  male  of  exceptional 
force.  When  the  ram  is  exhausted,  according 
to  the  theory  of  cross  sexual  heredity  the 
males  ought  to  be  more  numerous.  It  ap- 
pears, therefore,  that  in  this  experiment  of 
Mayerhofer's  we  have  something  which  re- 
mains in  want  of  explanation.  We  shall  pres- 
ently have  occasion  to  speak  more  fully  of 
the  facts  which  this  author  communicates 

47 


SCHENK'S   THEORY 

respecting  the  origin  of  sex  in  man,  and  will 
then  return  to  this  subject. 

The  information  which  we  have  concerning 
a  stallion  (Sir  Hercules)  belonging  to  the  stud 
of  Count  Lehndorff  deserves  attention.  This 
stallion  was  twenty-six  years  old,  and  had  to 
cover  twenty-three  mares.  The  result  was 
twenty-four  foals  of  the  male  sex.  This  case 
of  the  ardent  mares  and  the  old  stallion  can 
be  explained  by  the  theory  of  cross-heredity 
of  sex. 

Particular  attention  should  be  here  directed 
to  a  phenomenon  which  seems  to  imply  that 
a  sexually  exhausted  individual  always  has 
his  advantage  of  propagating  his  own  sex 
secured.  It  is  a  sort  of  fulfilment  of  duty  on 
the  part  of  a  strong  female  animal  when 
her  litter  shows  a  majority  of  male  individ- 
uals, or  male  individuals  only.  In  this  con- 

* 

nection  may  be  mentioned  the  facts  communi- 
cated by  Settegast,  Nathusius-Hundisburg, 
and  De  la  Tellais,  who  arrived  at  their  results 

48 


THE   DETERMINATION   OF  SEX 

from  experiments  upon  the  proportions  of  the 
sexes  of  the  offspring  of  the  domesticated 
mammalia. 


"  Attempts  to  solve  the  problem  of  the  origin 
of  difference  of  sex  by  means  of  experiments 
have  been  numerous.  So  early  as  the  last 
century  Platz  attempted  to  carry  out  experi- 
ments with  living  animals. 

The  temperaments  of  the  breeding  couple 
ought  to  be  concordant.  Both  should  be 
either  of  warm  or  cool  temperament.  Warmth 
and  moisture  are  primary  conditions  of  fer- 
tility, not  in  plants  alone,  but  amongst  the 
animals  also;  and  (as  Mayoor  Zsigmond,  of 
Kaschau,  proclaimed  in  1723)  represent  the 
primary  conditions  of  the  possibility  of  a  con- 
ception. 

The  warm  element  belongs  to  the  man;  the 
moist  to  the  woman.  Where  both  qualities 
are  to  be  found  in  both,  offspring  may  also 
be  anticipated.  But  if  this  be  not  the  case, 

4  49 


SCHENK'S   THEORY 

for  example,  if  the  man's  warmth  does  not 
accord  with  that  of  his  wife,  but  is  of  a 
higher  degree,  then  he  can  beget  boys.  If 
he  be  not  so  warm,  he  must,  if  he  wishes 
for  sons,  make  a  distinct  alteration  in  his 
diet.  According  to  the  prescription  given, 
he  ought  to  lead  a  regular  life  and  to  limit 
himself  strictly  to  warm  and  dry  aliments. 
The  temperament  of  the  woman  is  often  ardent 
and  dry.  In  this  state  it  must  be  regarded 
as  unfitted  for  the  development  of  an  embryo. 
Befitting  food  would  not  be  without  an  in- 
fluence upon  the  alteration  of  temperament. 
Respecting  this,  experiments  had  proved  this 
much,  that  a  suitable  change  of  diet  can  ex- 
ercise a  salutary  influence  over  the  tempera- 
ment. A  woman  who  was  in  the  highest 
degree  beautiful  in  face  and  in  every  part 
comely  had  a  temperament  which  would  ac- 
cord with  that  of  any  man. 

Then  comes  the  theory  of  the  allotment  of 
the  male  and  female  in  man,  and  in  all  the 

50 


THE  DETERMINATION  OF  SEX 

vertebrata,  to  the  right  and  left  sides  of  or- 
gans of  generation.  This  is  a  theory  which 
is  being  always  brought  forward,  even  by  the 
most  recent  writers,  some  of  whom  go  so  far 
as  actually  to  wish  to  support  it  by  experi- 
ments. 

Thus  the  excision  of  one  or  the  other  of 
the  testicles  of  the  male  is  recommended  in 
order  that  the  owner  may  be  able  to  breed 
the  sex  which  he  desires.  It  still  remains,  in 
order  to  effect  the  artificial  determination  of 
the  sex,  that  the  female  should  also  play  her 
part  correctly,  so  that  the  semen  of  the  male 
may  be  conveyed  to  an  ovule  from  the  re- 
quired ovary.  An  effort  was  accordingly 
made  to  secure  intercourse  in  such  a  man- 
ner that  the  semen  of  the  male  might  be 
delivered  in  a  certain  direction  in  agreement 
with  the  anatomical  position  of  the  duct 
which  was  to  lead  the  seed  into  the  required 
ovary.  But  it  was  practically  difficult  to  settle 
what  position  in  the  intercourse  was  the  right 

51 


SCHENK'S   THEORY 

one.  Experience  proved  that  in  a  certain 
case  on  two  successive  occasions  male  indi- 
viduals were  born  when  the  impregnation 
had  been  so  contrived  that  the  semen  should 
enter  the  right  ovary.  Therefore  the  left 
ovary  was  for  female  offspring.  It  is  not 
our  concern  to  enter  into  further  explana- 
tions of  these  occurrences.  Only  this  much 
may  be  said,  that  experiments  have  been 
constantly  made  which  might  lead  to  some 
conclusive  solution  of  these  questions,  with- 
out any  result  having  been  obtained. 


A  publication  appeared  in  the  year  1786 
dealing  with  the  above-mentioned  theory,  and 
at  the  time  attracted  much  attention.  It  has 
now  become  difficult  to  procure,  and  is  often 
mentioned  on  account  of  its  containing  much 
that  is  valuable  for  influencing  sex,  both 
amongst  men  and  animals,  that  has  been 
gathered  from  all  the  authors  of  the  previ- 
52 


THE   DETERMINATION   OF  SEX 

ous  century,  and  more  especially  from  all  the 
ancient  authors  who  had  written  on  this  sub- 
ject. 

The  author  was  J.  Ch.  Hencke,  organist  at 
Hildesheim,  and  the  title  of  his  book,  'The 
Secret  of  Nature  Completely  Discovered,  both 
in  the  Procreation  of  Man,  and  for  the  abso- 
lute choice  of  the  Sex  of  Children.*  Bruns- 
wick, 1786.  (Vollig  entdecktes  Geheimniss  der 
Natur,  sowohl  in  der  Erzeugung  des  Mens- 
chen  als  auch  in  der  willkurlichen  Wahl  des 
Geschlechts  der  Kinder.  Braunschweig,  1786.) 
The  author  relies  upon  exploded  theories,  ac- 
cording to  which  the  offspring  is  evolved,  as 
it  were,  out  of  a  mixture  of  the  generative 
secretions  of  the  two  sexes,  and  can  be  in- 
duced to  develop  into  either  a  male  or  female 
individual.  Thus  the  sex  is  not  previously 
determined,  only  in  the  course  of  its  devel- 
opment out  of  the  developing  mass,  which 
consists  of  a  mixture  of  male  and  female 
generative  secretions,  distinctive  sexual  char- 

53 


SCHENK'S   THEORY 

acteristics  make  their  appearance,  according 
to  the  predominance  of  the  male  or  female 
portion  of  the  mixture.  But  here,  also,  the 
old  theory  is  set  forth  very  precisely.  The 
generative  matter  of  the  right  testicle  serves 
to  fructify  ova  from  which  males  are  devel- 
oped, that  of  the  left  testicle  is  used  to  fruc- 
tify and  develop  female  ova.  Similarly,  the 
tenet  is  propounded  that  the  right  ovary  con- 
tains male  ova  and  the  left  such  only  as  will, 
when  developed,  produce  female  offspring. 


These  doctrines,  as  a  basis  for  the  breed- 
ing of  animals,  Hencke  had  discovered  by 
castrating  swine,  dogs,  and  rabbits.  Thus  it 
happened  that  a  boar,  who,  after  castration, 
had  only  the  left  testicle,  twice  running  bred 
with  a  sow  female  young  only.  Similar  phe- 
nomena occurred  with  other  animals,  so  that 
this  method  was  recommended  by  the  au- 
thor to  the  breeders  of  his  time.  But  it 

54 


THE   DETERMINATION  OF  SEX 

happened,  also,  that  a  surgeon  upon  open- 
ing the  body  of  a  woman  who  had  had 
sons  only  and  never  a  single  daughter, 
found  the  left  ovary  very  thin  and  with- 
ered, so  that  it  was  hardly  possible  that  it 
could  serve  for  the  development  of  a  new 
individual.  On  the  contrary,  the  right  ovary 
was  in  a  normal  condition.  It  now  remained 
only  to  discover  some  device  for  man,  by 
which  he  might  be  able,  during  the  act  of 
generation,  to  avail  himself  of  the  discoveries 
thus  made,  so  as  to  obtain  the  result  of  an 
absolute  choice  of  the  sex  of  the  offspring. 
The  ligation  of  one  of  the  testicles  was 
Hencke's  infallible  remedy.  When  this  severe 
proceeding  proved  impracticable,  in  its  place 
was  substituted  an  elevation  of  the  testicle 
by  means  of  its  suspending  muscle  (the  cre- 
master).  Under  certain  conditions  this  takes 
place  of  itself  in  particular  positions,  and  was 
accordingly  recommended  as  an  established 
proceeding  for  men. 

55 


SCHENK'S    THEORY 

One  other  conclusion  of  Hencke's  deserves 
particular  mention.  He  was  bold  enough  not 
only  to  assert  that  the  right  and  left  sexual 
glands  served  exclusively  for  the  generation 
of  male  and  female  individuals,  respectively, 
but  also  asserted  that  the  generative  matter 
from  the  right  or  left  gland  of  one  parent 
was  productive  only  when  united  with  that 
of  the  same  gland  of  the  other  parent.  His 
counsels  were  not  for  such  persons  as  are  too 
heated,  too  ardent.  (<  For  young,  hot,  hasty 
men,"  he  says,  (<who  are  altogether  with- 
out consideration,  I  am  not  writing;  but  for 
chaste  married  people,  and  especially  for 
those  to  whom  the  production  of  a  child  of 
one  or  the  other  sex  is  a  matter  of  impor- 
tance. » 

Couteau  established  the  fact  that  each  sem- 
inal duct  had  its  own  orifice,  through  which 
the  semen  was  poured  into  the  urethra.  This 
fact  was  in  his  days  of  the  greatest  impor- 

56 


THE  DETERMINATION  OF  SEX 

tance,  as  it  prevented  any  mixture  of  the 
semen  of  a  man's  two  testicles.  Hencke 
firmly  insisted  that  the  semen  was  discharged 
by  one  testicle  or  seminal  vesicle  alone,  in 
the  case  when  the  testicle  was  raised  up. 
But  we  need  not  here  follow  further  Hencke 's 
theories  which  he  deduced  from  his  own  ex- 
periments. In  the  present  day  these  theories 
will  satisfy  no  one.  Results  which  have  been 
obtained  either  after  ovariotomy,  or  after  the 
extirpation  of  testicles,  have  made  us  per- 
fectly certain  about  the  value  of  one  or  the 
other  generative  gland  for  the  production  of 
the  male  or  female  sex.  The  case  of  Schatz, 
which  has  been  also  pointed  to  us  as  impor- 
tant in  other  specialist  works,  may  not  be 
uninteresting  here.  The  left  ovary  of  a 
young  girl  was  removed,  together  with  a 
portion  of  the  left  tube,  and  the  right  ovary, 
also,  with  the  exception  of  a  margin  of  about 
two  millimetres'  breadth.  When  she  was  mar- 
ried she  gave  birth  to  a  girl,  whereas  a  boy 

57 


SCHENK'S    THEORY 

should  have  been  expected,  seeing  that  only 
male  offspring  were  to  be  produced  by  the 
right  ovary. 

Scarcely  any  work  that  lies  before  us  on 
this  subject  is  so  much  regarded  as  that  of 
Hencke.  At  the  same  time,  and  although  it 
had  in  its  day  the  widest  circulation,  it  fre- 
quently met  with  the  most  unqualified  condem- 
nation. Dr.  von  Seligson,  in  his  discourse  before 
the  Society  of  Medical  Practitioners  at  Moscow 
(1895),  on  tne  subject  of  influencing  the  de- 
velopment of  sex,  in  connection  with  Hencke's 
theory,  attached  value  to  a  great  number  of 
experiments  tending  to  support  the  old  view. 
It  was,  however,  admitted  that  by  a  departure 
of  nature  from  the  ordinary  law  (somewhat 
resembling  a  transposition  of  the  viscera)  male 
or  female  ova  might  occur  in  the  respectively 
opposite  ovaries. 

De  Bay,  who  was  opposed  to  the  theory  of 
the  anteriorly-developed  sexual  products  of 

58 


THE   DETERMINATION  OF  SEX 

the  right  and  left  ovaries,  asserts  that  the 
quality  of  the  generative  products  depends 
upon  the  quantity  of  nitrogen  existing  in  the 
chemical  composition  of  the  ovum  and  the 
semen.  A  large  proportion  of  nitrogen  in 
the  ovum  occasions  the  development  of  a 
girl.  If,  on  the  contrary,  the  semen  contains 
a  great  quantity  of  nitrogen,  a  male  individual 
will  result.  To  determine  the  proportion  of 
nitrogen,  or  to  give  it  scientific  value  in  such 
cases,  seems  to  be  a  difficult  matter. 


Mention  is  also  made  of  cases  of  tubal 
pregnancy  in  which  the  sex  was  determined, 
and  an  effort  has  been  made  here,  also,  to  find 
some  support  for  the  theory  of  the  existence 
of  sex  in  the  ovum  whilst  in  the  ovary  on 
the  right  or  left  side.  Fourteen  of  these 
tubal  pregnancies,  described  by  different  au- 
thors, showed  boys  on  the  right  and  girls  on 
the  left  side.  (Seligson.)  In  such  anomalous 

59 


SCHENK'S    THEORY 

cases  where  the  embryo  has  developed  itself 
in  the  Fallopian  tube,  and  has  not  reached 
the  uterine  cavity,  there  is  no  doubt  that  the 
developed  ovum  originated  in  the  ovary  of 
the  side  on  which  it  was  found. 

Efforts  are  made  to  confute  the  different 
objections  raised  in  many  quarters.  The  men- 
tion made  by  the  traveler,  Peter  Kolben,  of 
the  practice  of  cutting  out  one  testicle,  which 
is  the  custom  of  certain  African  tribes  (this 
is  contradicted  by  Le  Vaillant  [1784],  and  by 
Fritsch  [1880]),  and  the  accounts  of  Otto 
Finsch,  may  not  deserve  credit,  as  they  rest 
upon  assertions  made  by  other  persons.  Ac- 
counts are  further  given,  drawn  from  medical 
experience,  of  men  who,  after  prolonged 
orchitis,  with  consequent  occlusion  of  the 
vas  deferens,  begot  only  children  of  one 
sex,  or  in  other  cases  were  unable  to  induce 
pregnancy.  Also  the  discharge  of  semen  was 
asserted  not  to  take  place  from  both  sper- 
matic ducts  at  the  same  time.  After  many 
60 


THE   DETERMINATION   OF  SEX 

digressions,  Seligson  in  the  end  adheres  to 
Hencke's  theory  on  no  sufficient  grounds,  and 
then  bases  on  that  theory  a  method,  upon 
which  I  shall  not  here  pass  judgment,  but 
merely  mention  it  without  describing  it. 

At  all  events,  there  can  be  no  question  of 
a  compression  of  the  spermatic  cord  in  any 
way,  for  it  could  not  be  accomplished,  either 
manually  or  with  the  aid  of  various  kinds  of 
apparatus,  without  giving  rise  to  excessive 
pain. 

In  this  case,  as  Hencke  in  his  time  ex- 
plained, the  cremaster  muscle  raises  the  tes- 
ticle up  towards  the  inguinal  canal.  At 
complete  erection  the  testicle  is  drawn  up 
and  pressed  against  the  inguinal  ring.  This 
gives  more  favorable  conditions  for  leading 
the  semen  forward  from  this  one  of  the  two 
testicles;  and  this  portion  of  the  semen  is 
used  for  impregnation,  to  which  end  also  a 
favorable  attitude  and  a  free  passage  into 
the  ovary  must  be  provided.  According  to 

61 


SCHENK'S    THEORY 

the  views  of  the  author,  this  method,  if 
adopted  in  procreation,  will  lead  to  the  de- 
sired result  of  producing  a  given  sex.  Ex- 
ceptions are  admitted.  Exceptions  occurred 
in  five  families  with  twenty-three  children. 
The  author  clings  firmly  to  his  theory  that 
each  testicle  possesses  its  own  special  sper- 
matozoa and  each  ovary  its  special  ova,  in 
which  a  given  sex  is  already  in  existence, 
and  from  which  in  fruitful  intercourse  male 
or  female  individuals  originate. 


Next  after  a  number  of  theories  which 
have  been  current  on  this  subject,  we  reach 
some  others,  to  which  more  or  less  value  has 
been  attributed.  Morello  attached  weight  to 
the  concentration  of  the  semen.  Thin,  liquid 
semen  was  to  be  favorable  to  the  production 
of  females;  thick  semen  produced  males.  Ac- 
cording to  modern  theories,  based  upon  obser- 
vation of  invertebrate  animals  (O.  Hertwig, 
Balfour,  Landois,  Minot,  and  others),  it  appears 
62 


THE   DETERMINATION  OF  SEX 

improbable  that  this  position  can  be  main- 
tained. The  supporters  of  this  theory  assert 
that  a  single  spermatozoon  suffices  for  the  fer- 
tilization of  an  ovule,  or  to  develop  the  ovum 
into  a  so-called  "oosperm,"  that  is  to  say,  to 
form  a  really  fertilized  ovum.  (Perhaps  the 
excess  of  semen  serves  for  the  earliest  nutri- 
tive processes  of  the  ovum;  which  would, 
however,  be  difficult  to  prove.)  This  fact 
has  been  also  confirmed  in  the  case  of  the 
higher  animals,  and  it  might  be  in  a  similar 
manner  brought  to  an  issue  in  the  case  of 
man.  However,  observations  of  this  kind 
have  not  yet  proved  possible  with  man.  But 
in  the  case  when  several  spermatozoa  pene- 
trate the  interior  of  a  single  ovum,  anomalies 
in  the  process  of  development  result  from 
the  formation  of  several  nuclei.  Such  ova, 
also,  perhaps  in  consequence  of  excess  of 
semen,  are  very  often  aborted  and  perish. 

In   order  to  throw  light  on  the  causes  de- 
termining   sex,   Pfliiger    (in    connection    with 

63 


SCHENK'S   THEORY 

results  obtained  by  Born,  which  will  be  cited 
later)  attempted  to  determine  the  relative 
numbers  of  the  sexes,  under  normal  condi- 
tions, in  the  case  of  the  frog  (Rana  fused). 
The  numbers  were  taken  by  his  pupils,  A. 
von  Griesheim  and  Dr.  W.  Kochs.  The 
identification  of  the  sex  was  made  with  a 
microscope  under  the  supervision  of  Pfluger. 
According  to  Pfluger  the  Graafian  follicles 
are  easily  identified  with  the  aid  of  a  micro- 
scope, if  they  are  not  in  their  earliest  stage. 
They  contain  an  ovum  with  a  scanty  yolk 
and  large  germinal  vesicles  with  germinal 
markings.  The  whole  is  surrounded  by  con- 
nective tissue. 

According  to  Pfluger,  the  epithelium  is 
wanting  in  such  very  young  follicles.  In 
these  frogs  after  their  metamorphosis  the 
testicle  consists  of  tubes,  with  multinuclear 
epithelia,  and  is  easily  distinguishable  from 
the  always  large  ovaries  of  the  tadpoles.  By 
different  concentrations  of  semen,  Pfluger 

64 


THE   DETERMINATION  OF  SEX 

attempted    to    influence    the    proportion    be- 
tween the  male  and  female  sexes. 

According  to  Pfluger,  there  are  normally 
found  amongst  frogs  in  a  state  of  nature  36.3 
per  cent,  males,  and  63.7  per  cent,  females. 
With  thinner  or  thicker  semen,  the  average 
number  can  be  altered.  With  thin  semen 
Pfluger  obtained  27.3  males  and  72.7  females 
per  cent.  With  concentrated  semen  he  ob- 
tained 39.4  males,  and  60.6  females.  Pfluger 
carried  out  some  other  experiments,  and 
came  to  the  conclusion  that  the  concentra- 
tion of  the  semen  or  the  extract  from  the 
testicles  exercised  either  a  very  small  influ- 
ence or  no  influence  at  all  upon  the  sex. 
When  he  took  an  average  result  from  all  his 
experiments,  he  found  that  out  of  806  frogs 
which  he  raised,  288  were  males.  Whilst  the 
normal  proportion  of  the  males  developed 
freely  under  natural  conditions  was  36.3  per 
cent.,  that  reached  by  experiment  was  35.7 
per  cent.  It  should  be  here  remarked  that 

5  65 


SCHENK'S    THEORY 


among  the  tadpoles  many  are  found  whose 
sex  is  not  yet  determined.  They  are  in  a 
hermaphrodite  condition,  out  of  which  they 
develop  into  either  males  or  females. 


Robin,  the  well-known  French  histologist, 
made  the  question  of  the  origin  of  sex  the 
subject  of  an  extensive  inquiry.  His  investi- 
gations start  from  the  following  point:  —  In 
warm  climates  the  whole  quantity  of  blood 
in  the  inhabitants  is  less  than  in  temperate 
zones.  The  process  of  respiration  in  the  in- 
habitants of  warm  climates  is  also  not  so 
free  as  in  the  case  of  those  who  inhabit 
temperate  or  cold  zones. 

From  this  it  would  seem  that  some  process 
connected  with  nutrition,  and  with  the  pas- 
sage of  nourishment  into  the  blood,  is  the 
cause  of  the  number  of  male  births  being 
greater  in  the  cold  zones  than  it  is  in  the 
temperate  zones,  or  in  the  inhabited  regions 

66 


THE   DETERMINATION  OF  SEX 

lying  nearer  to  the  equator.  It  would  fol- 
low from  these  considerations,  that  if  the 
women  were  subjected  to  such  a  regime  as 
would  materially  affect  their  respiration  and 
the  quality  of  their  blood,  more  boys  than 
girls,  or  the  contrary,  might  be  bred.  If  so, 
breathing  an  atmosphere  containing  more  oxy- 
gen, with  a  corresponding  diet,  would  be  the 
right  receipt  for  producing  in  the  woman  such 
a  basis  that  in  the  course  of  development  the 
male  generative  organs  (which  Robin  considers 
the  anatomically  more  perfectly  developed) 
might  be  evolved  instead  of  the  female.  Ac- 
cording to  Robin,  the  male  sexual  apparatus 
in  comparison  with  that  of  the  female  is  pro- 
vided with  the  more  perfectly  developed  char- 
acter. Robin  further  insists  that  strong  men 
will  beget  more  male  individuals.  Further, 
that  a  woman  who  indulges  in  sexual  inter- 
course somewhat  seldom  has  female  children; 
and  that  voluptuous  women,  who  are  fruitful, 
generally  bear  boys.  A  number  of  experi- 

67 


SCHENK'S    THEORY 

ments  with   domesticated   mammalia  are   ad- 
duced in  support  of  this  view. 


Hegar  teaches  that  in  the  case  of  a  merely 
rudimentary  development  of  the  germinal 
gland  either  sex  is  developed. 

With  the  views  of  Robin  may  be  connected 
also  other  suggestions  regarding  the  food  of 
the  parents.  These  have  been  tried  both  with 
men  and  animals.  But  we  shall  not  here  go 
further  into  them.  Nor  shall  we  mention  the 
different  kinds  of  food  or  drink  which  have 
been  employed,  whether  by  men  or  women, 
to  produce  a  greater  sexual  activity. 


The  eminent  naturalist  Born,  of  Breslau, 
made  a  long  series  of  experiments,  which 
are  of  the  highest  interest  in  reference  to  the 
doctrine  of  the  origin  of  sex.  It  is  easy  to  fer- 
tilize frogs'  eggs  artificially.  The  ripe  eggs  are 

68 


THE  DETERMINATION  OF  SEX 

taken  directly  from  the  female,  and  the  tes- 
ticles of  the  male  rubbed  with  water.  This 
fluid,  which  now  contains  spermatozoa,  serves 
to  fertilize  the  eggs.  Spallenzani  had  already 
undertaken  artificial  fructification.  Born  ob- 
served, during  his  study  of  the  course  of  de- 
velopment, that  the  effect  of  his  breeding  as 
regarded  sex  was  to  produce  95  per  cent,  of 
females.  This  number  is  evidently  so  re- 
markable that  it  ought  to  secure  particular 
attention.  No  such  extreme  contrast  between 
the  numbers  of  males  and  females  is  to  be 
found  amongst  the  frogs  that  develop  freely 
under  natural  circumstances.  It  seemed  to 
Born  that  his  result  was  to  be  referred  to 
insufficient  nourishment,  and  that  the  tad- 
poles, being  somewhat  unfavorably  circum- 
stanced, had  not  been  able  to  attain  the 
development  of  the  stronger  sex.  In  this  ex- 
periment on  the  evolution  of  sex  it  appeared 
that  not  only  was  there  an  excessive  produc- 
tion of  females,  but  that  the  other  organs  of 

69 


SCHENK'S    THEORY 

the  embryo  and  its  whole  constitution  could 
be  modified  by  means  of  nutrition.  It  is 
also  to  be  observed  respecting  this  most  in- 
teresting experiment  that  many  of  the  tad- 
poles perished  of  hunger.  Now,  the  number 
of  still-born  males  of  the  human  species  very 
much  exceeds  the  number  of  still-born  girls. 
The  mortality  amongst  males  is  so  great  that 
the  average  is  from  136  to  140  still-born  boys 
to  100  still-born  girls.  An  attempt  has  been 
made  (Pfluger)  to  explain  this  phenomenon 
in  the  human  subject  on  the  ground  that  the 
tenacity  of  life  in  the  female  sex  in  the 
period  of  embryonal  existence  exceeded  that 
of  the  male.  Consequently,  boys  would  more 
easily  perish  during  development  than  girls. 
If  this  observation  made  with  respect  to  hu- 
man beings  were  applied  to  the  tadpoles,  it 
might  also  explain  the  high  percentage  which 
the  females  showed  among  the  frogs.  Very 
likely  the  male  tadpoles  possessed  less  capacity 
of  resistance;  or,  in  other  words,  were  less 

70 


THE   DETERMINATION  OF  SEX 

tenacious  of  life  than  the  females.  It  will 
be  understood  that  this  view  would  apply  only 
as  a  partial  explanation  of  the  facts  set  forth 
by  Born. 

In  the  artificial  breeding  of  trout,  which  is 
conducted  under  cover,  in  which  process  the 
embryos  which  have  crept  out  of  the  ovarian 
follicle  are  kept  with  the  yolk-sacs  in  small 
reservoirs  under  a  continuous  flow  of  water, 
it  is  observed  that  single  individuals  develop 
themselves  further.  They  lose  their  store  of 
yolk  with  the  yolk-sacs.  In  the  course  of  their 
further  development  and  nutrition  they  arrive 
only  very  slowly  at  the  development  of  the 
internal  generative  organs.  Even  in  a  very 
advanced  stage  the  sex  is  not  yet  so  plainly 
indicated  as  in  fish  of  the  same  size  living 
free.  Indeed,  it  is  even  affirmed  by  many 
persons  of  experience  that  in  the  artificial 
breeding  of  trout  even  those  that  have  at- 
tained their  full  growth  remain  unfruitful  and 


SCHENK'S    THEORY 


cannot  be  used  for  further  breeding.  (D'Aude- 
ville  and  Arens  raised,  in  the  case  of  trout, 
more  females  by  dry  impregnation.) 


Here  might  be  adduced  also  many  other 
doctrines  of  greater  or  less  interest  respect- 
ing the  theory  of  the  origin  of  sexual  dis- 
tinction. Only  in  order  that  I  may  not  intro- 
duce too  much  literary  matter,  I  shall  mention 
only  a  few  of  the  more  important  and  notice- 
able theories  before  I  return  once  more  to 
the  experiments  upon  the  influence  of  food 
upon  the  development  of  sex.  Janke's  work 
(small  edition),  published  at  Stuttgart  in  1896, 
furnishes  a  synopsis  of  the  literary  work 
done,  as  do  other  books  which  treat  of  this 
subject. 

Mons.  Thury,  professor  at  Geneva,  pub- 
lished at  Leipzig,  in  the  year  1863,  a  book 
on  the  law  of  breeding  the  sexes,  which, 

72 


THE  DETERMINATION  OF  SEX 

on  account  of  its  contents,  attracted  great 
attention.  In  this  work  the  author,  after  a 
number  of  successful  experiments  and  other 
investigations,  shows  how  an  influence  may 
be  exerted  over  the  sex  of  plants,  animals, 
and  men. 

This  work  stirred  me  up  to  the  endeavor 
to  devote  myself  to  this  question,  so  far  as 
that  might  be  possible.  I  shall  give  a  short 
sketch  of  Thury's  work,  together  with  the 
critical  revision  of  it  by  Dr.  H.  A.  Pagen- 
stecher,  of  Heidelberg. 

The  doctrine  respecting  the  origin  of  sex 
in  cattle  was  laid  down  by  Thury  from  his 
own  investigations.  The  principal  point  in 
his  doctrine  of  the  origin  of  sex  in  animals 
he  considers  to  be  the  condition  of  the  ovum 
at  the  time  when  it  is  fertilized.  If  the  ovum 
has  reached  the  stage  of  ripeness,  which  may 
be  described  as  an  advanced  stage,  we  may 
expect  to  have,  after  fertilization  has  taken 
place,  a  male  individual,  which  will  develop 

73 


SCHENK'S   THEORY 

itself  out  of  the  ovum.  ,  If,  however,  the 
ovum  has  reached  only  an  imperfect  state  of 
ripeness  when  successful  impregnation  takes 
place,  then  no  such  powerful  and  perfect 
specimen  of  the  race  as  the  male  is  can  be 
developed,  and  the  result  of  such  an  ovum  is 
always  a  female. 

From  this  it  follows  that,  according  to 
Thury,  the  cause  of  sex  lies  in  the  ovum  de- 
veloping itself  in  the  ovary,  and  the  degree 
i  of  its  ripeness  is  the  only  factor  in  the  de- 
'velopment  of  one  sex  or  the  other. 

It  is  not,  however,  shown  what  the  systems 
are  by  which  such  an  ovum  can  be  correctly 
judged,  so  as  to  determine  the  different  de- 
grees of  ripeness.  We  now  know  very  well 
certain  signs  which  appear  upon  the  matura- 
tion of  the  ovum,  of  which  we  shall  not  say 
more  here.  Of  these  Thury  could  know  noth- 
ing in  1863,  because  at  that  time  they  had 
not  been  discovered. 

74 


THE   DETERMINATION  OF  SEX 

Thus  the  sex  depends  upon  the  ripeness 
of  the  female's  ovum  at  the  time  of  its  fec- 
undation. In  the  case  of  its  having  reached 
the  highest  degree  of  ripeness,  a  male  is  the 
result.  It  is  impossible  for  the  ovum  to 
attain  a  higher  degree  of  ripeness.  If  the 
ovum  of  a  human  female  has  arrived  at  this 
supreme  degree  of  ripeness,  it  has  reached 
that  stage  in  which  it  is  capable  of  becoming 
the  basis  of  the  most  perfect  living  creature 
which  exists  upon  our  globe. 

Rutting  is  an  external  sign  of  the  maturity 
of  the  ovum  amongst  the  lower  animals. 
When,  during  the  rutting  period,  an  ovum  is 
detached  from  the  ovary,  and  passes  through 
the  Fallopian  tubes  to  the  cavity  of  the 
uterus,  the  fructification  can  take  place  at 
the  beginning  of  the  rutting  period.  At  this 
period  its  ripeness  is  not  so  far  advanced. 
The  result  of  the  development  of  such  an 
ovum  is  a  female.  But  when  the  fecundation 
has  taken  place  at  the  end  of  the  rutting 

75 


SCHENK'S    THEORY 

period,  the  ovum  has  reached  its  highest  de- 
gree of  development,  and,  if  effectively  fec- 
undated, it  will  become  a  male.  It  follows 
that  the  signs  of  rutting  should  be  carefully 
studied,  as  in  fact  is  habitually  done  by 
practical  farmers.  The  duration  of  the  rut- 
ting period  and  the  influences  which  affect 
fertilization  should  be  accurately  known  in 
order  to  lead  to  any  practical  result. 

Females  at  their  first  conception  would 
usually  produce,  or  would  be  particularly  dis- 
posed to  produce,  female  individuals.  Experi- 
ments succeed  better  with  such  as  have  often 
produced  young.  In  their  case  the  symptoms 
which  indicate  the  commencement  or  the  con- 
clusion of  the  rutting  are  much  more  easily 
determined,  so  that  they  are  better  adapted 
for  these  experiments. 


We  know  well  that  in  the  case  of  the 
lower  animals  when  rutting,  as  in  the  case  of 
the  human  female  during  menstruation,  an 

76 


THE   DETERMINATION  OF  SEX 

ovum  is  liberated  from  the  follicle  in  the 
ovary,  and  ordinarily  passes  away  in  the  men- 
strual discharge.  In  fact,  a  follicle  of  the 
ovary  bursts,  and,  to  be  precise,  that  one 
which  protrudes  most  beyond  the  surface  of 
the  ovary.  This  bursting  of  the  follicle  has 
not  actually  been  observed.  But  that  this 
event  takes  place  there  can  be  no  doubt,  for 
the  locality  of  the  fissure  is  perceptible,  and 
the  ovum  is  found  either  at  hand  on  the 
ovary,  or  else  on  the  fimbria.  The  increase 
of  fluid  in  the  follicle  of  the  ovary,  and  the 
excessive  charge  of  blood  in  the  vessels  on 
the  walls  of  the  follicle,  seem  to  be,  without 
any  actual  contraction  taking  place,  the  phys- 
iological causes  of  the  freeing  of  the  ovum 
from  the  follicle,  so  that  it  may  come  in  con- 
tact with  the  semen.  Ovulation  can  take 
place  without  intercourse.  But  sexual  inter- 
course can  also  favor  ovulation;  at  least,  it 
appears  to  facilitate  the  separation  of  the 
ovum  from  the  ovary. 

77 


SCHENK'S   THEORY 

Bischoff  made  known  the  fact  of  the  sepa- 
ration of  the  ovum  from  the  follicle.  He 
showed  that  the  presence  of  sperm  in  the 
feminine  organs  of  generation  of  the  animals 
was  indifferent,  that  the  rutting  of  the  ani- 
mal was  the  index  of  the  ripeness  of  the 
ovum.  Eimer,  Beneke,  Van  Bamecke,  and 
Hensen,  call  attention  to  the  phenomenon 
which  is  observed  in  the  case  of  bats,  who 
for  a  whole  month  before  the  detachment  of 
the  ovum  from  the  follicle  have  their  uteri 
full  of  semen. 


These  processes  which  take  place  at  rutting 
time  are  attended  with  sexual  excitement 
and  congestion  of  the  external  genitals.  It 
is  not,  however,  necessary  that  these  proc- 
esses should  in  the  case  of  all  animals  occur 
at  the  same  time  as  ovulation.  If  rutting 
animals  are  restrained  from  sexual  inter- 
course, the  sexual  excitement  of  the  female 
passes  off;  but  the  symptoms  of  rutting  again 

78 


THE   DETERMINATION   OF  SEX 

make  their  appearance  after  a  time.  These 
are  the  phenomena  of  the  so-called  rutting 
season. 

This  rutting  season  lasts  with  sheep  four- 
teen days,  with  swine  fifteen  to  eighteen 
days;  with  cows,  horses,  and  apes  four  weeks. 
It  corresponds  to  the  menstruation  of  the 
human  female  (Hensen).  Many  bitches  ad- 
mit the  dog  only  when  six  or  seven  days 
have  elapsed  since  the  issue  of  blood.  In  the 
case  of  many  animals  rutting  is  marked  by  a 
flow  of  blood  from  the  genitals.  This  is  the 
case  with  apes,  bitches,  swine,  and  many 
other  mammalia. 


Under  these  circumstances,  the  symptoms 
of  rutting  are  sufficiently  distinctly  marked 
to  make  it  possible,  as  Thury  suggests,  to 
determine  the  advanced  state  of  ripeness  or 
its  commencement  in  the  ova.  But  it  is 
scarcely  possible  to  say  when  the  period  of 
ripeness  commenced  in  this  ovum  or  that. 

79 


SCHENK'S    THEORY 

An  ovum  which  had  begun  to  ripen  early 
may,  at  the  beginning  of  the  rutting  time, 
have  attained  to  the  condition  of  a  male- 
producing  ovum.  At  the  same  time,  others 
which  are  fertilized  at  the  conclusion  of  the 
rutting,  but  had  begun  to  ripen  compara- 
tively late,  may,  at  the  end  of  the  rutting 
time,  not  yet  have  advanced  far  enough  to 
be  able  to  develop  male  individuals. 


Thury  bases  his  doctrine  on  a  number  of 
phenomena  of  the  vegetable  and  animal 
world,  and  upon  various  experiences  in  the 
case  of  man.  He  also  adduces  many  statis- 
tical data  in  explanation  and  support  of  his 
theory. 

The  observations  on  plants  make  it  indis- 
putably clear  that  all  the  circumstances  which 
favor  growth  and  ripening  are  favorable 
conditions  for  the  development  of  male  or- 
gans. If  all  these  circumstances  are  lacking, 
female  organs  are  produced. 
80 


THE   DETERMINATION  OF  SEX 

Dark  and  cold,  for  instance,  cause  the  male 
organs  to  perish.  In  recent  times  a  great 
number  of  extended  studies  of  the  phenom- 
ena of  vegetable  life  in  this  direction  have 
appeared.  I  may  mention  more  particularly 
the  following  experiments  made  by  M.  von 
Treskow  in  Gorlitz  with  Ariscema  (Verhand- 
lungen  des  Botanischen  Vereins  der  Provinz 
Brandenburg,  1895).  This  plant  first  pro- 
duces male  flowers.  In  the  later  year,  when 
it  has  become  larger,  it  produces  female 
flowers.  The  transition  from  the  male  flowers 
of  the  early  stage  to  the  female  flowers  of 
the  later  stage  can  be  hastened  at  pleasure 
by  planting  in  rich  garden  mold  and  manur- 
ing with  horn  shavings.  If,  on  the  other 
hand,  the  plant  be  placed  in'  poor,  sandy  soil, 
it  reverts  to  the  male  flowers.  The  same  au- 
thor quotes  in  his  essay  a  remark  of  Heyer's 
(Halle,  1884),  who  declares  that  no  sufficient 
observations  exist  respecting  the  influence 
which  different  situations  exert  over  sex. 
6  81 


SCHENK'S   THEORY 

I  adduce  this  instance,  for  the  sake  of  re- 
marking respecting  it,  that  on  this  subject 
also  controversies  exist,  which  must  be  settled 
by  wider  studies  of  the  life  of  plants. 

Cornaz  has  tried  to  derive  from  cows  evi- 
dence in  support  of  Thury's  theory.  He  had 
twenty-nine  cows  impregnated  with  attention 
to  the  rutting  time,  and  from  twenty-nine 
births  received  twenty-two  females  and  seven 
males.  Cornaz  attested  his  experiment  by  a 
declaration,  and  the  experiment  was  repeated 
in  the  French  state  domains. 

But  the  experiment  alone  was  striking 
enough  to  invite  repetition.  It  also  met  with 
partial  success.  But  the  plan  was  afterwards 
entirely  given  up,  perhaps  in  consequence  of 
disappointments. 

In  this  case  it  very  likely  happened  —  as  in 
such  experiments  it  very  easily  may  happen 
—  that,  in  consequence  of  insufficient  practi- 
cal knowledge  on  the  part  of  the  experimenter, 
the  actual  commencement  of  the  rutting  time 
82 


THE   DETERMINATION  OF  SEX 

was  overlooked.  In  addition,  it  is  well  known 
that  animals,  in  consequence  even  of  an 
amount  of  exercise  not  very  exhausting,  and 
in  many  other  ways,  as  well  as  in  conse- 
quence of  the  food  they  have  taken,  may 
exhibit  variations  in  the  activity  of  their  rut- 
ting. It  is  not,  therefore,  surprising  if  the 
results  of  experiments  show  much  that  was 
unexpected. 

I  here  pass  over  a  great  number  of  proofs 
which  Thury  gives  in  his  essay.  Funcke 
(1866)  made  in  his  r  Physiology >  the  following 
remarks  on  Thury's  theory:  — <( Although  the 
origin  and  determination  of  sex  is  not  indis- 
putably proved  to  depend  upon  the  degree 
of  ripeness  of  the  ovum,  it  appears  to  me 
that  we  have  not  reached  the  right  time  for 
determining  the  factor  upon  which  it  does  de- 
pend. These  experiments  have  been  made  to 
repose  upon  a  fact,  which  fact  certainly  proves, 
beyond  the  possibility  of  dispute,  a  relation 
between  the  fertilization  of  the  ovum  and  the 

83 


SCHENK'S    THEORY 

subsequent  sex.  This  fact  is  that,  in  the 
case  of  certain  creatures  capable  of  partheno- 
genesis (unisexual  procreation),  we  find  that, 
from  unfertilized  ova  one  sex  always  results, 
and  from  fertilized  ova  the  other.  But  any 
closer  interpretation  of  this  function  of  the 
semen  is  rendered  nugatory  in  advance  by 
this,  that  it  is  in  some  cases  the  male  and 
in  others  the  female  that  results  from  the 
unfertilized  ova." 


Thury's  theory  can  be  very  suitably  brought 
into  agreement  with  the  theory  of  cross- 
heredity  of  sex,  and  explained  by  the  assist- 
ance of  that  view.  The  cow,  at  the  begin- 
ning of  her  rutting,  is  not  in  a  condition  of 
great  sexual  vigor.  If  the  ovum  be  effectually 
fertilized,  it  may  be  supposed  that  the  bull, 
in  procreative  activity  the  superior  consort, 
will  be  fitted  not  to  reproduce  his  own  sex, 
but  that  of  the  weaker  cow.  At  the  end  of 
the  rutting  period  the  cow,  which  is  brought 


THE   DETERMINATION  OF  SEX 

to  the  bull,  has  her  ovum  ripened  to  the 
highest  possible  degree,  and  in  consequence, 
when  compared,  from  a  sexual  point  of  view, 
with  the  bull,  is  distinctly  the  stronger  and 
superior,  and  a  male  calf  is  in  this  case  the 
result  of  conception. 

According  to  the  theory  of  cross-heredity 
of  sex,  female  creatures  should  in  the  former 
instance  be  produced,  and  in  the  latter  males, 
which  same  result  is  reached  in  accordance 
with  the  theory  of  Thury. 

Attempts  have  been  also  made  to  apply 
Thury's  theory  to  the  human  species.  The 
menstruation  of  women  has  been  compared 
with  the  rutting  of  the  lower  animals,  and 
has  been  considered  a  protracted,  oft-repeated 
rutting.  Now,  as  an  ovum  is  specially  de- 
veloped every  month,  it  follows  that  this 
ovum  requires  a  certain  part  of  a  month  to 
attain  a  more  or  less  advanced  degree  of 
ripeness.  According  to  this,  the  ova  which 
are  fertilized  a  short  time  after  menstruation 

85 


SCHENK'S    THEORY 

will  develop  only  female  individuals,  whilst 
those  which  have  had  a  longer  time  in  which 
to  attain  to  ripeness  would  develop  them- 
selves into  males. 

The  mucous  membrane  of  the  womb  ought, 
about  ten  days  before  the  beginning  of  men- 
struation, to  thicken  itself  distinctly  in  conse- 
quence of  a  turgescence  and  dilatation  of  the 
vessels.  In  consequence  it  appears  swollen 
and  loosened,  and  it  has  reached  the  culmi- 
nating point  of  swelling  when  the  menstrua- 
tion is  at  its  highest.  After  menstruation 
the  swelling  does  not  immediately  decrease, 
but  lasts  on  for  about  nine  days,  until  the 
mucous  membrane  returns  to  its  normal  con- 
dition. (Hensen.)  Thus  it  seems  that  the 
swelling  and  hyperaemia  in  the  womb  appear 
at  the  same  time  as  the  conditions  which  lead 
to  the  ripening  of  the  ovum.  The  fertiliza- 
tion of  the  human  ovum  would  be,  therefore, 
most  efficacious  at  the  time  when  the  mucous 
membrane  of  the  womb  is  also  most  appro- 

86 


THE   DETERMINATION  OF  SEX 

priately  prepared,  and  it  is  probable  that  the 
same  moment  is  the  one  when  all  the  other 
coincident  factors  are  of  a  sort  best  calculated 
for  the  reception,  the  fixing,  and  the  protec- 
tion of  the  ovum.  It  is  simultaneously  with 
these  processes  in  the  mucous  membrane  of 
the  womb,  and  in  the  other  parts  of  the  gen- 
erative organs  of  the  woman,  that  the  ripen- 
ing of  the  ovum  is  effected. 

Now,  it  may  appear  not  to  be  a  matter  of 
indifference  (and  may  very  likely  even  have 
some  connection  with  the  development  of 
sex)  whether  the  ovum  is  fertilized  at  a 
period  during  which  the  mucous  membrane 
is  passing  through  its  changes  in  order  to 
reach  its  highest  point  of  swelling,  or  at  the 
time,  when,  after  menstruation,  the  mucous 
membrane  is,  during  so  considerable  a  period 
(nine  days),  passing  through  a  retrograde 
metamorphosis  in  order  to  return  to  its  nor- 
mal condition.  This  protracted  process  seems 
to  correspond  to  the  protracted  rutting  in  the 

87 


SCHENK'S   THEORY 

form  of  a  menstruation.  If  so,  the  human 
uterus,  as  Thury's  theory  would  declare, 
would  be  prepared,  to  a  certain  extent,  in 
different  ways,  for  the  reception  of  the  ovum, 
according  to  the  different  sex-conditions  of 
the  future  child. 


It  is  not  sufficiently  known  to  how  great 
an  extent  the  principles  of  Thury's  theory 
have  hitherto  found  their  right  application  to 
the  case  of  man.  They  seem  in  practice  to 
be  applied  in  different  ways. 

It  seems  that  in  cases  where  a  result  was 
obtained  it  could  be  more  easily  explained  by 
the  principles  which  have  been  already  de- 
scribed under  the  theory  of  cross-heredity  of 
sex.  The  assumption  of  a  greater  or  lesser 
degree  of  ripeness  of  the  ovum  which  was  to 
be  developed  was  a  very  questionable  one. 

The  different  processes  with  which  we 
have  become,  in  more  recent  times,  ac- 
quainted as  symptoms  of  the  ripening  of  the 

88 


THE   DETERMINATION  OF  SEX 

ovum,  are  not  here  intended.  Such  symptoms 
can  be  observed  both  in  the  ova  of  the  in- 
vertebrata  and  in  those  of  the  vertebrata. 
These  symptoms,  which  are  such  as  the  at- 
tainment of  the  normal  size  of  the  ovum  of 
the  species  in  question,  the  protrusion  of  the 
orientation  points  (Richtungskorpercheri),  the 
steps  towards  the  formation  of  a  female  an- 
terior nucleus  (V or  kern),  etc.,  do  not  here 
apply,  for  the  recognition  of  that  higher  de- 
gree of  ripeness  in  the  ovum  which  is  neces- 
sary at  the  time  of  fructification  for  the 
development  of  a  male  individual. 

All  the  above  symptoms  occur  alike  in  the 
ova  destined  for  the  male  and  for  the  female 
sex.  That  ripeness  of  the  ovum  upon  which 
Thury's  theory  insists,  lies  in  the  nature  of 
the  ovum  apart  from  any  anatomical  signs. 
It  is  a  condition  of  the  ovum  which  we  can 
only  attempt  to  explain  by  laying  down  the 
principle  that  an  ovum  which  has  been  for  a 
longer  time  prepared  in  the  female  generative 
89 


SCffENJCS    THEORY 


organs  previously  to  its  fertilization,  must  be 
riper  than  another  which  has  had  less  time  for 
this  preliminary  process. 


We  have  mentioned  above  that  on  the 
occasion  of  Thury's  experiment,  the  desired 
result  was  effected  in  twenty -nine  cases. 
Pagenstecher,  Siebold,  and  Koll  have  dealt 
critically  with  Thury's  work.  Coste  was  not 
in  a  position  to  confirm  these  experiments, 
nor  to  verify  them.  In  order  to  test  Thury's 
results  as  applied  to  the  human  subject, 
Schroder  obtained  the  assistance  of  young 
women,  who  were  in  a  position  to  give  him 
positive  and  accurate  information  respecting 
the  time  at  which  they  became  pregnant. 
The  women  could  name  the  day  on  which 
they  had  had  sexual  intercourse,  and  knew 
the  date  of  the  last  menses.  From  careful 
calculation  of  the  interval  between  these 
dates,  it  was  possible  to  ascertain  approxi- 
90 


THE   DETERMINATION   OF  SEX 

mately  at  what  stage  impregnation  of  the 
ova  took  place,  the  degree  of  ripeness  of  the 
impregnated  ova  could  also  be  inferred  from 
the  space  of  time  that  had  elapsed  since  the 
last  menstruation,  and  the  sex  of  the  foetus 
was  noted.  Schroder  found  that  on  an  aver- 
age of  twenty-six  cases  in  which  boys  were 
born,  the  conception  had  taken  place  10.08 
days  after  menstruation;  on  an  average  of 
twenty-nine  cases  in  which  girls  were  born, 
9.76  days  after.  In  consequence,  he  was  not 
able  to  confirm  Thury's  theory  in  the  case  of 
the  human  subject. 


The  experiments  of  Albini  in  Naples  (ac- 
cording to  Kronecker's  report  ^Centralblatt  fur 
medicinische  Wissenschaft ?  1868),  which  he 
made  during  four  years  in  his  great  poultry- 
yard  showed  in  the  first  place  that  hens  for 
eight  days  after  being  separated  from  the 
cock  laid  none  but  fertile  eggs.  On  the 
ninth  and  tenth  day  the  fertile  and  infertile 

91 


SCHENICS   THEORY 

eggs  were  of  equal  number.  On  the  twelfth 
day  all  the  eggs  were  infertile.  Nevertheless 
fertile  eggs  appeared  even  on  the  eighteenth 
day.  It  is  possible  that  they  had  been  impreg- 
nated by  spermatozoa  which  had  remained 
in  the  folds  of  the  mucous  membrane  of  the 
uterus. 

Hens  never  yet  impregnated,  or  such  as 
had  not  been  impregnated  for  at  least  a 
month,  in  three  days  (after  impregnation) 
laid  fertile  eggs,  which  increased  in  number 
daily. 

According  to  Albini,  hens  can  in  Naples 
leave  the  eggs  which  they  are  hatching.  The 
shell  can  be  partly  broken  off  and  again  re- 
placed without  the  embryos  necessarily  per- 
ishing. But  care  must  be  taken  that  no 
fungoid  growth  reaches  the  germ,  as  this 
is  easily  fatal  to  it.  Indeed,  it  has  been 
recently  shown  that  new-laid  or  well-pre- 
served eggs  are  free  from  all  micro-or- 
ganisms. When  these  appear  they  have 

92 


THE   DETERMINATION   OF  SEX 

made  their  way  into  the  egg  through  the 
mechanically  injured  or  otherwise  altered 
calcareous  shell.  They  do  not  have  their 
origin  in  the  egg  from  the  mother.  The  egg 
of  the  bird  is  perfectly  free  from  micro- 
organisms when  it  is  laid.  If,  however,  only 
traces  of  pure  cultivations  of  micro-organisms 
be  in  a  suitable  way  applied  to  such  eggs 
externally  (Lenderer).  they  always  have  a 
fatal  effect  upon  the  developing  germ,  even 
when  they  are  not  any  of  the  so-called  patho- 
genic microbes. 

And  now  the  result  of  Albini's  breeding 
experiments  upon  poultry  with  respect  to  the 
origin  of  sex. 

From  three  to  six  days  after  intercourse 
with  the  cock  the  hens  lay  eggs,  from  which 
on  the  average  an  equal  number  of  males 
and  females  are  developed.  In  the  warmer 
part  of  the  year  the  number  of  males  appears 
to  be  greater. 

93 


SCHENK'S   THEORY 

Better  nourishment  of  parents  seems  also  to 
exercise  an  influence  over  the  sex  of  the  young. 

Such  eggs  as  were  laid  from  ten  to  fifteen 
days  after  complete  separation  from  the  cock, 
gave  when  hatched  generally  a  distinctly 
greater  number  of  females.  Albini  found 
that  the  greater  number  of  these  died  of 
anaemia.  He  ascribed  that  to  imperfect  fer- 
tilization, and  considered  that  development  of 
an  excessive  number  of  females  was  to.  be 
ascribed  to  the  same  cause. 

Albini  inclines  towards  the  theory  of  Thury, 
in  accordance  with  which  the  principal  cause 
of  the  development  of  sex  lies  in  the  degree 
of  ripeness  of  the  ovum.  He  is  opposed  to 
the  theory  of  Coste  and  Gerbe,  which  de- 
clares that  the  ova  of  the  birds  and  mammals 
are  fertilized  when  they  fall  from  the  ovary. 
The  place  where  this  took  place  was,  according 
to  their  theory,  exactly  localized,  at  the  open- 
ing of  the  Fallopian  tube,  and  not  at  any 
place  in  the  length  of  the  tube. 

94 


THE   DETERMINATION  OF  SEX 

Fertilization  in  the  Fallopian  tube  or  uterus 
is  allowed  to  be  possible,  and  it  is  admitted 
that,  in  exceptional  cases,  fertilization  of  the 
hen's  egg  is  possible  so  long  as  it  is  not  sur- 
rounded by  the  shell-membrane. 

This  opinion,  however,  is  in  direct  contra- 
diction to  that  of  Lenkart  and  Newport  and 
many  others,  who  hold  that  the  albumen, 
which  gathers  around  the  yolk  in  the  oviduct, 
hinders  the  penetration  of  the  spermatozoa 
into  the  yolk.  When  Albini  had  collected  his 
facts  he  came  to  the  conclusion  that,  in  the 
case  of  animals  which  bear  many  young,  the 
last  are  mostly  male,  and  explains  this  by 
the  hypothesis  that  the  ova  passing  through 
the  Fallopian  tube  thrust  the  semen  back,  so 
that  the  ova  which  come  behind  are  therefore 
fertilized  in  a  more  advanced  stage. 


Meyer  believes  that  he  has  incontestably 
proved  against  Ahlfeld  that  the  sex  is  deter- 
mined at  conception.  He  does  not  appear  to 

95 


SCHENK'S    THEORY 

be  disposed  to  admit  the  existence  of  male  and 
female  ova  in  the  ovary;  but  he  thinks  it 
absolutely  certain  that  the  sex  is  determined 
at  conception  by  the  reciprocal  action  of  the 
ovum  and  the  semen.  This  view  follows  from 
the  fact  that,  as  Thury's  theory  demands,  a 
fertilization  and  a  determination  of  the  sex 
must  necessarily  take  place  as  regards  time 
either  at  the  beginning  or  the  end  of  the 
mingling  of  semen  and  ovum. 

The  longer  the  ovum  exists  free  from  the 
ovary,  the  longer  it  remains  without  the  sur- 
rounding of  those  elements  (contained  in  the 
ovary)  which  are  necessary  to  it.  Apparently, 
in  consequence  of  the  absence  of  these  ele- 
ments, it  is  all  the  time  drawing  nearer  ex- 
tinction, or  it  may  at  least  become  gradually 
less  capable  of  maintaining  its  own  sex  — 
which  is  feminine.  At  least,  it  appears,  be- 
fore it  is  overtaken  by  the  total  extinction 
which  threatens  it  if  it  is  not  fertilized,  to 
lose  the  energy  necessary,  when  fertilization 
96 


THE   DETERMINATION  OF  SEX 

ensues,  to  maintain  its  sex,  and  so  may  be- 
come fitted  to  assume  the  opposite  masculine 
sex.  This  much,  however,  seems  to  be  quite 
certain,  according  to  Mayerhofer,  that  the 
human  ovary  does  not  contain  male  and  fe- 
male ova  already  possessed  of  sex.  Equally 
impossible  is  it  to  imagine  male  and  female 
seminal  filaments  (spermatozoa)  already  exist- 
ing in  the  organism,  and  provided  with  dis- 
tinct capacities  for  generating  definite  sexes. 
We  are  unacquainted  with  any  special  ana- 
tomical signs  indicating  any  such  distinction, 
and  do  not,  even  after  microscopic  investiga- 
tion, find  ourselves  prompted  to  assume  the 
existence  of  such  distinct  forms  as  would 
allow  us  to  conclude  the  existence  of  so  fun- 
damental a  difference.  It  is  true  that  in 
many  of  the  lower  animals  different  forms  of 
spermatozoa  are  known.  These  are  developed 
in  one  and  the  same  testicle,  and  under  the 
microscope  whisk  about  confusedly  with  viva- 
cious movements.  We  find  this  in  the  case 

7  97 


SCHENK'S    THEORY 

of  a  kind  of  snail  (Murex  brandaris).  If  we 
observe  a  drop  of  the  semen  of  this  creature 
diluted  with  sea  water,  the  greater  number 
of  the  spermatozoa,  possessing  head,  central 
portion,  and  tail,  move  about  very  energetic- 
ally. Amongst  them  are  other  spermatozoa, 
distinctly  larger  and  of  different  form,  whose 
shape  suggests  spindle-like  elements,  ending 
in  thin  thread-like  tails.  All  these  objects 
exhibit  a  striking  vivacity  of  movement. 
Whether  these  objects  represent  a  particular 
kind  of  spermatozoa  (as  some  have  supposed), 
exhibiting  definite  sexual  character,  or  whether 
they  are  not  cells,  striking  on  account  of  their 
movements,  out  of  which  spermatozoa  are 
developed  (the  so-called  spermatides  or  sper- 
matogonia,  transition  forms  out  of  which  sper- 
matozoa are  developed),  is  at  present  an  open 
question. 

H.  A.  Pagenstecher  attempted  an  important 
readjustment  of  Thury's  theory,  and  tried  to 
show  that  it  might  be  made  concordant  with 
98 


THE   DETERMINATION  OF  SEX 

what  had  been  elucidated  by  previous  obser- 
vations. He  holds  fast  to  the  axiom  (Joh. 
Muller,  Home,  Geoffrey  St.  Hilaire,  etc.),  that 
the  embryo  is  at  first  sexless,  and  that  the 
ovum  after  its  fertilization  still  has  this  char- 
acter, and  must  possess  the  potentiality  of 
developing  its  sex  in  two  different  directions. 
The  factors  which  determine  sex  must  be 
external  to  the  embryo. 

Pagenstecher  remarks  that  the  relations 
which  have  existed  anterior  to  the  fertilization 
of  the  ovum,  as  well  as  its  age  (with  which 
its  ripeness  is  connected),  are  from  the  outset 
without  influence  on  sex. 

The  embryonal  germ,  before  its  fertiliza- 
tion, is  an  embryo  whose  sexual  development 
is  undetermined.  In  this  case  fertilization 
acts  as  an  external  factor  in  the  direction  of 
determining  the  sexual  quality  of  this  inde- 
terminate embryo. 

The  act  of  impregnation  would  be  of  influ- 
ence upon  the  sex  of  the  embryo  in  accord- 

99 


SCHENK'S    THEORY 

ance  with  the  character  of  the  father.  That 
follows  from  Pagenstecher's  explanations  of 
Hofacker's  observations.  According  to  Ho- 
facker  we  get  from  men  of  twenty-four  years 
of  age  and  upwards,  as  also  from  sheep  of  a 
certain  age,  an  average  of  a  greater  number 
of  males.  In  the  case  of  mothers,  also,  as  we 
have  already  pointed  out,  the  sexually-stronger 
age  (Lenkart,  Girou  de  Bouzareingues,  Ho- 
facker,  Morel  de  Vinde,  Sadler)  and  the  food 
have  an  influence  upon  the  majority  of  births 
of  female  individuals.  Here  should  be  added 
the  experience  of  Nasse  and  Van  den  Bosch. 
The  observations  of  Dzierzon,  von  Siebold, 
Lenkart,  and  von  Berlepsh,  on  the  develop- 
ment of  sex  in  bees,  and,  according  to  von 
Siebold,  among  the  Psychids,  should  also  be 
taken  into  consideration.  When  the  females 
of  certain  Pyschids  are  not  impregnated  they 
lay  only  female  ova.  If  they  are  impreg- 
nated, male  ova  appear  also.  The  tree-lice 
(Cestoni,  Reaumur)  give  birth  to  living  young 


THE   DETERMINATION  OF  SEX 

without  impregnation.  These  are  at  first  only 
female,  afterwards  males  appear  as  well. 
After  this  impregnation  commences,  and  the 
females  begin  to  lay  ova. 

The  experiments  of  Knight,  who  found 
that  melons  and  cucumbers  produce  male 
blossoms  under  higher  temperature  and  fe- 
male under  lower  (which  was  verified  by 
Mauz),  demonstrate  that,  in  this  case,  such 
external  factors  as  warmth,  light,  dryness, 
have  an  influence  upon  sex.  Pagenstecher, 
however,  believes  that  the  conditions  of  origin 
of  sex  are  not  the  same  in  animals  and  plants. 
We  must  not,  he  says,  from  these  observa- 
tions draw  conclusions  off-hand  respecting  the 
sexual  propagation  of  plants  nor  of  animals 
in  general. 

It  must  be  further  pointed  out  with  regard 
to  the  thesis  that  ova  which  are  emitted  last 
have  had  more  time  to  ripen,  that  we  must 
reflect  whether  the  process  of  ripening  may 
not  have  also  begun  late. 

101 


SCHENK'S   THEORY 

Thury's  observation  that  the  last  egg  laid 
by  a  singing  bird  developed  a  male  (commu- 
nicated by  O.  Bourrit),  and  that  in  the  case 
of  hens  the  majority  of  the  later  eggs  were 
males,  seemed  to  Pagenstecher  not  quite  cer- 
tain. He  mentions  also  a  method  by  which, 
in  poultry  breeding,  the  breeding  experiments 
can  be  conducted  on  a  regular  principle, 
which  I  shall  quote  word  for  word:  — 

<(  For  this  experiment  a  number  of  hens  are 
taken  which  may  be  anticipated  to  be  (<  set- 
ters,w  unless  the  use  of  incubators  is  preferred. 
The  hens  are  to  be  separated,  and  the  eggs 
which  each  one  lays  in  her  own  particular 
nest  are  to  be  marked  with  numbers  corre- 
sponding to  the  days  on  which  they  were  laid. 

<(The  eggs  of  the  different  hens  are  now  to 
be  rearranged,  so  that  the  eggs  which  each 
particular  hen  is  given  to  hatch  shall,  as 
nearly  as  possible,  have  the  same  numbers. 
For  example,  if  the  number  of  the  hens  be 
six,  and  the  period  of  laying  up  to  the  time 

102 


THE   DETERMINATION  OF  SEX 

when  the  hens  begin  to  set  be  thirty  days, 
one  hen  will  have  eggs  to  hatch  with  the 
numbers  i  to  5,  the  next  6  to  10,  the  third 
ii  to  15,  the  fourth  16  to  20,  the  fifth  21  to 
25,  the  sixth  26  to  30. 

(<  In  this  way  the  doubt  will  be  avoided, 
which  necessarily  arises,  if  I  give  the  eggs  of 
one  hen,  although  marked,  to  be  hatched  by 
her  alone. 

<(  In  the  latter  case,  it  can  very  seldom  be 
known  with  certainty  from  which  egg-shell  a 
cock  or  hen  issued. 

(<In  this  experiment,  on  the  contrary,  one 
can  quietly  wait  until  the  cocks  and  hens  in 
the  growing  broods  of  the  different  hens  can 
be  clearly  distinguished  and  numbered,  see- 
ing that  each  brood  has  numbers  (of  the  days 
of  laying)  of  very  nearly  the  same  value. 
The  experiment  is  easier  and  less  subject  to 
the  possibility  of  error  when  the  eggs  belong 
to  different  varieties  and  are  taken  from 
known  parents." 

103 


SCHENK'S   THEORY 

Fertilization  in  many  cases  alters  the  future 
sex  as  soon  as  it  affects  the  germ  in  some 
corresponding  manner.  The  germ  develops 
itself,  and,  in  the  case  of  creatures  whose 
ova  develop  without  fertilization,  evolves  one, 
or  the  other,  or  both  of  the  sexes.  Accord- 
ing to  Pagenstecher,  fertilization  often  alters 
the  determination  of  the  sex  of  the  germs 
which  attain  to  development  in  the  ova. 
The  point  of  time  in  the  life  of  an  ovum,  at 
which  it  has  reached  that  degree  of  ripeness 
which  gives  it  such  a  character  that  the 
semen  can  no  longer  affect  the  determination 
of  the  sex,  cannot  be  absolutely  settled.  A 
more  powerful  bull  might  beget  female  calves 
earlier  in  the  late  rutting  time  than  an  older 
one. 

After  further  explanations  and  critical  ex- 
positions, which  suggest  themselves  in  the 
course  of  the  examination  of  the  theory,  Pa- 
genstecher lays  stress  upon  the  following 
important  dicta  of  Thury's  teaching:  — 

104 


THE   DETERMINATION   OF  SEX 

1.  Sex   depends   upon  the    ripeness   of    the 
ovum  at  the  time  of  fertilization. 

2.  The  ovum  which,  at  the  moment  of  fer- 
tilization, has   not   yet  reached   a   certain  de- 
gree of  ripeness,  produces  a  female.     If  this 
degree  of  ripeness  has  been  passed,  the  ovum, 
upon  fertilization,  produces  a  male. 

3.  If  at  the  time  of  rutting  a  single  ovum 
is    detached    from    the    ovary,    and    descends 
slowly    through    the    genital    canal    (animals 
which    bear    a    single    offspring),  fertilization 
taking  place  at  the  beginning  of  the  rutting 
suffices  to  produce  a  female,  and  at  the  end 
of   the   rutting   to   produce   a   male,  provided 
that  the  change  in  the  condition  of  the  ovum 
takes     place     normally     during     its     passage 
through  the  genital  canal. 

Both  the  theory  as  Thury  stated  it,  and  the 
critical  remarks  that  have  been  made  upon 
it,  have  been  further  elucidated  in  many  sub- 
sequent works.  Here  Pictet,  Chavannes,  C. 
Vogt,  De  Philippi,  and  others,  have  taken 

105 


SCHENK'S    THEORY 

part.  Pictet  believes  in  the  uniformity  of 
the  sexual  life  of  vegetables  and  animals,  so 
that  both  would  be  subject  to  identical  fun- 
damental laws. 

The  facts  which  stand  in  certain  relations 
with  the  fundamental  laws  are  numerous,  and 
the  manner  in  which  they  tend  to  affect  those 
fundamental  laws  occasions  various  combina- 
tions in  the  variety  of  phenomena. 

For  the  animal  kingdom  Thury  adduces  a 
number  of  observations  as  the  foundation  of 
his  teaching.  We  shall  here  turn  our  atten- 
tion to  some  of  them. 

We  have  already  pointed  out  that  in  the 
case  of  the  eggs  of  the  singing  birds,  which 
are  laid  by  turns,  the  young  which  emerges 
from  the  last  strikingly  smaller  egg,  the  so- 
called  (<  nest  egg,  *  is  always  a  male. 

According  to  the  theory  of  Thury,  the 
ripeness  of  the  ovum  depends  also  upon  the 
place  which,  in  the  animals,  it  occupies  in 
the  ovary.  In  consequence,  according  to  this 

106 


THE  DETERMINATION  OF  SEX 

author,  it  is  not  improbable  that  we  shall  find 
an  irregularity  in  the  successive  production 
of  male  and  female  ova. 

If  the  activity  of  the  generative  apparatus 
of  the  female  should  be  increased  by  any 
circumstance,  in  the  case  of  the  animals  the 
ripening  of  the  ovum  would  be  accelerated. 
The  consequence  would  be  an  earlier  detach- 
ment or  emptying  out  of  the  ova  from  the 
ovary.  In  consequence,  the  generative  oper- 
ations in  the  animal  are  of  a  more  complex 
nature  than  in  plants,  a  fact  which  is  of 
great  significance  for  the  determination  of  sex. 

The  continuous  intercourse  of  the  male 
with  the  female  increases  the  capacity  for 
accelerating  the  ripening  of  the  ovum.  Ac- 
cording to  Burdach  the  mother  animals  who 
do  not  have  frequent  intercourse  with  the 
male  bear  more  females,  because  their  ova  do 
not,  before  fertilization,  attain  so  high  a  de- 
gree of  ripeness  as  to  be  able  to  develop  into 
males.  Also,  it  appears  from  observations  on 

107 


SCHENK'S    THEORY 

animals,  not  to  be  improbable  that  the  male 
chooses  the  time  of  intercourse.  The  deter- 
mination of  the  chosen  time  depends  upon 
many  influences.  The  causes  of  choice  may 
be  sought  in  many  factors.  Some  of  these 
depend  upon  external  influences;  others  have 
internal  causes.  The  causes  may  be  general 
or  personal.  They  may  depend  upon  external 
form,  or  be  occasioned  by  other  phenomena 
of  the  animal  world.  It  is  always  easy  for 
these  phenomena,  which  in  their  nature  are 
of  the  most  different  kinds,  to  escape  obser- 
vation. 

Amongst  cattle  and  sheep  the  first-born  are 
more  often  females.  (Girou.)  Also  in  the  hu- 
man species  a  greater  number  of  females  are 
observed  amongst  the  first-born.  Here,  on 
the  one  hand,  regular  intercourse  with  the 
male  is  to  some  extent  unfamiliar;  whilst,  also, 
according  to  Thury,  the  choice  of  the  date  of 
marriage  might  be  of  importance.  The  con- 
stancy of  the  births  may  be  explained  by  the 
108 


THE   DETERMINATION  OF  SEX 

regularity  of  the  intercourse  of  the  two  par- 
ents in  consequence  of  the  reciprocal  ties 
which  surround  family  life. 

From  illegitimate  births  more  girls  result 
than  from  marriage.  The  reason  of  this 
might  be  sought  in  the  influence  of  the  active 
excitement  of  the  female  at  the  time  at  which 
the  conception  took  place,  that  is,  shortly  after 
menstruation,  when  the  woman  is  most  easily 
excitable. 

The  various  theories  respecting  the  explana- 
tion of  the  production  of  sex  which  are  known 
to  us,  from  the  earliest  accounts  down  to  the 
modern  predominance  of  natural  philosophy, 
have  been  collected  by  W.  His.  (^Archiv  fur 
Anthropologie^  Band  4,  5.) 

Since  then,  it  is  true,  during  the  course  of 
successive  studies,  and  more  especially  of 
those  which  have  been  made  during  the  pres- 
ent century,  many  substantial  alterations  have 
appeared  in  the  views  held  respecting  the 

109 


SCHENK'S    THEORY 

cause    of    the    different   development   of    sex. 
We  have  seen  this  above. 

Thus,  discoveries  have  been  made  which 
have  exercised  a  very  wide  influence,  for 
example,  that  of  the  ovum  in  man  and  in 
the  other  mammalia  (Baer,  1828),  or  the 
penetration  of  the  spermatozoa  into  the  proto- 
plasm of  the  ovum  as  a  necessary  condition 
of  fertilization.  In  later  times  it  has  been 
made  certain  that  the  head  of  the  spermat- 
ozoon is  a  nucleus,  and  that  only  one  sper- 
matozoon penetrates  into  the  interior  of  the 
ovum.  Afterwards  its  head  as  a  nucleus 
unites  with  a  nucleus-part  of  the  ovum, 
forming  a  new  nucleus  in  the  ovule,  which, 
together  with  the  surrounding  protoplasm, 
serves  as  the  point  of  departure  of  the  fur- 
ther processes  of  development,  and  in  this 
condition  is  described  as  an  oosperm.  After 
this  follow  other  extensive  details  of  the 
process  of  development,  which  will  not  be 
described  here.  It  may  be  already  seen, 

no 


THE  DETERMINATION  OF  SEX 

from  the  few  principal  factors  of  the  process 
mentioned,  that  our  theory  respecting  the  de- 
velopment of  the  sex  in  the  embryo  will 
have  to  be  substantially  altered.  We  shall 
here  adduce  only  the  fundamental  doctrines 
respecting  the  development  of  the  generative 
organs  laid  down  by  Waldeyer  in  his  mas- 
terly work  on  the  ovary  and  the  ovum.  The 
teaching  for  which  we  are  indebted  to  His, 
Kolliker,  Schafer-Korschelt,  Heider,  Duval, 
Kollmann,  Minot,  Bonnet,  Bergh,  Prenant, 
Balfour,  Romiti,  Kuppfer,  and  others,  must 
also  be  well  remembered,  as  well  as  the  ac- 
quisitions of  new  information  connected  with 
the  physiology  of  the  embryo,  and,  of  quite 
recent  date,  the  mechanism  of  development 
(Roux),  which  can  acquaint  us  more  espe- 
cially with  the  particulars  respecting  the 
states  and  processes  in  the  ovule  during  the 
earliest  life-stages  of  its  development. 

The  doctrines  of   the  physiology  of   metab- 
olism   in    men     and    beasts    under    different 

in 


SCHENK'S    THEORY 

circumstances  have  exercised  so  powerful  an 
influence  over  our  comprehension  of  the  rela- 
tions of  the  individual  during  the  sexual-life, 
that  we  practically  find  in  all  these  teachings 
a  powerful  support,  whence  we  may  obtain 
many  elucidations  bearing  upon  the  question 
lying  before  us,  and  may  discover  the  prin- 
ciples necessary  to  complete  our  theory. 

But,  before  entering  upon  the  fundamental 
principles  of  the  theory  which  I  have  set 
forth,  I  wish  to  mention  a  treatise  of  Mayr- 
hofer's,  the  principal  results  of  which  I 
shall  briefly  recapitulate.  After  that  I  shall 
mention  briefly  such  information  as  I  have 
met  with  respecting  the  nutrition  of  the 
mother. 

Mayrhofer  was  led  by  critical  notices  and 
the  observations  of  others,  and,  further,  by  his 
own  experiences,  to  conclusions  which  he  set 
forth  in  propositions,  some  of  which  I  select 
here. 
.  ;  In  the  plants  and  the  lower  animals  fooci 

112 


THE   DETERMINATION  OF  SEX 

plays  a  principal  part  in  the  development  of 
sex.  The  sex  is  not  generated,  but  depends 
upon  external  influences  over  the  fruit  which 
is  in  a  state  of  development.  And  here  we 
have  a  stage  which  precedes  the  separate  sex 
in  man,  in  which  stage  sexual  neutrality  must 
be  regarded  as  normal,  where  also  we  find  a 
kind  of  hermaphroditism. 

Whether  sex  in  the  human  species  is  deter- 
mined at  conception,  or  only  develops  itself 
afterwards,  we  must  attempt  to  discover  from 
obstetric  experience. 

The  twins  and  triplets  contained  by  one 
chorion  are  of  the  same  sex,  and  have  a  com- 
mon placenta  in  which  the  blood  passages  of 
both  umbilical  cords  communicate  with  one 
another.  On  this  account,  also,  many  opine 
that  the  identity  of  sex  is  occasioned  by  the 
intermixture  of  the  blood,  an  opinion  regarded, 
on  the  contrary,  by  others,  with  incredulity, 
because  the  intermixture  of  the  blood  might 
very  possibly  lead  merely  to  a  mixture  and 
8  113 


SCHENK'S   THEORY 

not  to  homogeneity,  under  which  circum- 
stances dissimilarity  of  development  would  be 
possible  enough.  We  may  here  adduce  the 
following  facts  also  (Jhering) :  The  armadilloes 
produce  a  number  of  young  in  one  litter, 
which  are  normally  developed  in  a  single 
chorion,  and  are  of  the  same  sex,  as  in  the 
case  with  man  when  twins  are  developed  in 
one  chorion. 

Heartless  monstrosities  (Acardiaci)  are,  in 
spite  of  imperfect  nutrition  (the  conditions  of 
proper  nutrition  by  the  blood  are  wanting  in 
the  embryo),  of  the  same  sex  as  normal  off- 
spring. Now,  cases  of  this  kind  demonstrate 
that,  in  the  later  periods  of  development, 
although  the  conditions  of  nutrition  are  not 
alike,  nevertheless  the  similarity  of  sex  in  the 
twins  is  maintained ;  so  the  foundation  of  the 
future  sex  would  be  laid  at  the  period  of 
conception.  This  rule  which  proves  valid  for 
the  twins  found  in  a  single  chorion,  would 
apply  for  all  human  ova  in  general,  because 
114 


THE   DETERMINATION  OF  SEX 

all  possess  the  capacity  of  attaining  their  sex- 
ual character  at  conception. 

According  to  Mayrhofer,  placentae  are  rare 
in  which,  where  there  are  two  chorions,  com- 
munication is  found  between  the  vessels  of 
the  two  umbilical  cords.  In  addition  to  what 
has  been  already  mentioned,  Mayrhofer  lays 
down  the  law,  which  we  find  frequently 
stated  in  many  quarters,  that  the  older  of 
the  two  parents  has  a  greater  preponderance 
in  favor  of  the  propagation  of  his,  or  her, 
sex.  Especially  the  physical  maturity  on  the 
man's  side  enables  him  to  propagate  his  own 
sex,  either  in  connection  with  younger  or 
older  women.  A  superiority  on  the  part  of 
the  woman  produces  girls. 

Our  author  only  partly  supports  Thury's 
theory,  and  considers  it  an  open  question 
whether  the  time  of  impregnation  has  any 
influence  on  the  origin  of  sex.  But  he  lays 
down  this  principle,  that  an  economy  of 
the  semen  by  infrequent  indulgence  in 

us 


SCHENK'S    THEORY 

intercourse  is  extremely  favorable  to  the  pro- 
duction of  males. 

It  may  be  possible  to  obtain  more  exact 
data  respecting  the  origin  of  sex  from  the 
artificial  breeding  of  fish.  In  this  case  the 
properties  of  the  sperm,  as  well  as  of  the  ova, 
might  be  observed  at  an  earlier  date  by  means 
of  a  fertilization  effected  externally.  Atten- 
tion might  be  also  paid  to  the  age  of  the 
parents.  In  short,  all  the  factors  of  artificial 
influence  upon  the  development  of  sex  can 
in  this  case  be  taken  in  hand  and  controlled 
by  varying  the  process  of  artificial  fertiliza- 
tion. The  author  does  not  appear  to  know 
that  the  results  obtained  by  artificial  breeding 
differ  remarkably  from  those  which  are  the 
consequence  of  the  natural  multiplication  of 
fish,  nor  that  the  development  of  sex  is  un- 
favorably affected  in  many  ways.  The  cause 
of  that  lies  very  likely  in  the  nutrition  of  the 
young  fry,  and  perhaps,  also,  partly  in  cross- 
breeding. 

116 


THE   DETERMINATION  OF  SEX 

What  influence  the  physical  welfare  of  the 
parents,  and  especially  of  the  mother,  has  on 
the  sex  of  the  offspring  in  man,  besides  other 
factors  deserving  of  attention,  ought  to  be 
discoverable  from  the  statistics  of  the  lying-in 
hospitals.  This  is,  in  my  opinion,  hardly  to 
be  expected. 

On  various  occasions,  whilst  taking  into 
consideration  the  possibility  of  an  influence 
on  the  part  of  the  parents  over  the  sex  of 
the  child  (in  such  respects  as  have  been  placed 
before  us  in  the  literature  dealing  with  this 
subject),  we  often  had  occasion  to  direct  at- 
tention to  the  food  of  the  parents.  And  espe- 
cially the  food  of  the  mother  seemed  to  us  to 
be  of  the  highest  importance. 

Now,  it  is  universally  known  that  metabo- 
lism is  increased  during  pregnancy.  The 
products  of  excretion  in  the  case  of  pregnant 
women  are  much  smaller  than  the  quantity 
of  matter  taken  in,  in  the  shape  of  food. 

117 


SCHENK^S   THEORY 

The  difference,  to  a  great  extent,  represents 
the  matter  taken  to  form  the  bodily  substance 
of  the  embryo,  in  accordance  with  the  ante- 
rior laws  which  have  been  fixed  by  the  doc- 
trines of  the  physiology  of  metabolism.  It 
will,  then,  be  necessary  to  pay  particular  at- 
tention to  the  investigation  of  metabolism. 
Suggestions  are  not  wanting.  They  will  be 
found  amongst  the  observations  of  leading 
specialists.  For  example,  Winckel  observed 
that  during  pregnancy  the  temperature  was 
slightly  raised.  This  increase  of  temperature 
must  practically  be  explained  as  due  to  the 
higher  and  more  productive  process  of  oxidi- 
zation, which  has  to  be  accomplished  by  the 
human  female  for  the  sake  of  nourishing  the 
foetus. 

During  pregnancy  the  number  of  blood 
corpuscles  suffers  an  observable  diminution. 
Still  plainer  is  the  reduction  of  the  quantity 
of  haemoglobin,  when  measured  with  Fleischl's 
haematometer.  This  last  phenomenon  is  very 

118 


THE   DETERMINATION   OF  SEX 

likely  connected  with  a  greater  consumption 
of  haemoglobin,  the  substance  being  used  up 
by  oxidization. 

Observations  of  setting  hens  are  not  with- 
out interest.  In  their  case,  also,  a  diminution 
of  haemoglobin  is  observable  during  the  pe- 
riod of  incubation.  The  haemoglobin  can  sink 
to  nearly  50  per  cent,  of  the  normal  amount. 
With  the  increase  of  haemoglobin  in  the  em- 
bryo and  its  simultaneous  diminution  in  the 
mother  during  incubation,  it  happens,  at  a 
certain  period  in  the  process  of  development, 
that  the  embryo  in  the  egg  and  the  setting 
hen  possess  a  nearly  equal  measure  of  haemo- 
globin with  a  nearly  equal  number  of  blood 
corpuscles.  An  increase  of  the  quantity  of 
haemoglobin  until  the  normal  amount  is 
reached  may  be  observed  in  both  towards 
the  end  of  incubation. 

The  Rhine  salmon  each  year  go  up  in  a 
well-nourished  condition  from  the  sea  into 
the  fresh-water  streams  to  spawn.  There 

119 


SCHENK'S    THEORY 

they  remain  several  months.  They  lose  much 
of  their  muscular  substance.  (Miescher.)  On 
the  other  hand,  a  great  development  of  the 
sexual  organs  and  of  sexual  secretions  takes 
place,  produced,  probably,  at  the  expense  of 
the  used-up  muscular  substance. 

Many  have  paid  particular  attention  to  the 
nourishment  of  the  maternal  organism.  In- 
vestigations have  also  been  published  dealing 
with  the  nutrition  of  the  parent  animals  in 
cases  when  it  was  desired  to  exercise  an  in- 
fluence over  the  sex. 

In  fact,  we  have  frequently  touched  upon 
such  subjects,  although  only  lightly.  Here, 
as  we  are  about  to  proceed  to  the  subjects  of 
nutrition  and  metabolism  in  the  human  fe- 
male awaiting  impregnation,  we  find  ourselves 
compelled  to  acquaint  the  reader  with  a  num- 
ber of  facts  which  permit  us  to  assume  a 
connection  between  the  food  supply  (includ- 
ing metabolism)  and  the  development  of  sex. 


120 


CHAPTER  III. 

ACCORDING  to  St.  Hilaire,  the  male  sex  is 
more  common  in  the  case  of  scantily  nourished 
(and  therefore  weakly)  animals.  Giron  de 
Buzareingues  says  that  the  same  is  sometimes 
the  case  with  domesticated  mammalia.  Mar- 
tegoute  has  found  that  the  sheep  which  bear 
female  offspring  are,  on  the  average,  of  a 
heavier  weight.  Furriers  have  remarked  that 
in  fruitful  regions  more  furs  of  female  ani- 
mals are  always  to  be  had  than  in  unfruitful 
districts.  It  would  follow  from  this  that  bet- 
ter nourishment  assists  the  production  of 
females. 

This  observation  seems,  however,  to  be  con- 
cordant with  the  general  practice  of  farmers, 
according  to  which  it  is  usual  to  keep  a 
greater  number  of  the  females  of  the  domes- 

121 


SCHENK'S    THEORY 

ticated  animals,  on  account  of  their  utility. 
The  males  are  kept  only  in  such  numbers  as 
may  be  absolutely  necessary  for  breeding  pur- 
poses, or  for  stronger  beasts  of  burden.  The 
surplus  is,  by  means  of  trade,  disposed  of  in 
other  regions.  In  consequence,  in  poor  un- 
fruitful districts,  the  number  of  males  is 
pretty  nearly  the  same  as  in  fruitful  regions, 
the  actual  requisite  number  being  in  both 
cases  about  the  same.  The  females,  on  the 
contrary,  can  be  much  better  kept  in  fruitful 
districts,  where  there  are  rich  and  fertile 
meadows  and  better  fodder,  than  in  the  poor 
regions.  In  the  latter  the  females  are  con- 
sequently rarer. 

Wilkens  attempted  to  apply  diet  to  the  pro- 
duction of  sex  in  the  domesticated  mammalia, 
and  laid  down  the  following  principles:  The 
food  must  be  of  influence  upon  the  embryo 
in  the  mother's  womb,  and  the  better  nourish- 
ment favors  the  female,  the  worse  the  male 
sex. 

122 


THE   DETERMINATION  OF  SEX 

We  have  already  mentioned  the  views  of 
Robin  and  Born  respecting  the  influence  of 
food. 

Busing  turned  his  attention  to  the  effect  of 
diet  upon  horses,  with  a  view  to  the  develop- 
ment of  sex. 

The  state  of  nutrition  of  the  parents 
would  have  an  influence  upon  the  develop- 
ment of  the  embryo.  In  this  case,  also,  the 
better  condition  produced  females,  the  worse 
males. 

According  to  Diising,  if  the  mother  was 
well  nourished,  old  semen  operating  upon  a 
young  ovum  would  produce  a  majority  of 
female  offspring.  On  the  other  hand,  if  the 
mother  was  insufficiently  fed,  young  semen 
operating  upon  an  old  ovum  would  produce  a 
majority  of  male  individuals. 

According,  to   Wappaens,    richer   or   poorer 
nourishment  in  years  of  different  fruitfulness 
in  Sweden  has  no  effect  upon  the  prevalence 
of  one  or  the  other  sex. 
123 


SCHENK'S    THEORY 

Ploss  also  tried  to  draw  attention  to  the 
fact  that  better  food,  in  the  case  of  the  male 
as  well  as  of  the  female  parent,  could  have 
some  effect.  Thus,  a  balance  of  the  numbers 
of  the  two  sexes  depended  upon  the  better 
or  worse  harvests  in  different  regions.  If  an 
excess  of  one  sex  appeared  in  one  year,  in 
consequence  of  an  abundance  of  food,  in  the 
next  year  unfavorable  circumstances  raised 
the  number  of  the  other  sex,  and  thus  a  pro- 
portion was  reached  which  represented  the 
normal  numbers. 

According  to  Piquet,  female  calves  are 
born  if  the  cow  is  poorly  fed.  This  diet 
should  last  some  weeks,  but  the  bull  should 
be  abundantly  fed  before  serving. 

According  to  Landois,  food  plays  a  most 
important  part  in  the  determination  of  sex 
amongst  insects.  If  the  germ  be  richly 
nourished,  females  are  principally  developed. 
(Landois,  ( Physiologic. >) 

A  great  number  of  different  foods  and 
124 


THE  DETERMINATION  OF  SEX 

drinks,  and  also  substances  which  have  direct 
medical  effects,  are  commonly  known  or  held 
to  exercise  an  effect  upon  the  activity  of  the 
generative  organs,  and  of  these  some  are  also 
recommended  under  medical  advice. 

Many  of  the  medicinal  substances  should 
be  carefully  avoided.  The  use  of  them  may 
prove  deleterious.  Cantharides,  or  various 
preparations  of  them,  as  well  as  other  sub- 
stances enumerated  under  this  head  in  phar- 
macology, are  distinctly  to  be  eschewed.  Not 
only  are  they  absolutely  incapable  of  exercis- 
ing any  influence  over  the  sex  of  the  future 
offspring,  but  they  can  also  be  distinctly  in- 
jurious to  the  whole  organism,  or  in  any  case 
to  the  urinary  and  generative  organs  in  this 
way,  that,  after  having  produced  their  effect, 
they  occasion  a  reaction,  which  leads  to  ab- 
normal conditions  and  inflammation  of  the 
kidneys.  No  expedient  of  this  kind,  no  food 
of  any  sort,  nor  drink,  should  ever  be  used, 
without  medical  advice.  Most  of  all  are  these 

125 


SCHENK'S    THEORY 

expedients   out   of   place   where  any  question 
exists  of  determining  the  sex  of  offspring. 

All  these  nostrums,  as  well  as  the  particu- 
lar kinds  of  food  or  drink,  exercise  only  tem- 
porarily a  certain  influence  over  the  activity 
of  the  sexual  organs,  exactly  as  they  do  in 
general  over  the  nervous  condition,  the  men- 
tal disposition,  humor,  etc.,  which  are  tempo- 
rarily stimulated. 

Herewith  may  be  classed  the  expedient  of 
the  injection  of  semen  recommended  by  Brown- 
Sequard,  in  consequence  of  which  people  of 
advanced  age  enjoy  a  feeling  of  rejuvenes- 
cence. His  first  experiment  was  tried  upon 
himself,  and,  in  spite  of  his  advanced  age,  he 
felt  himself  quite  fresh  and  young.  Originally 
the  injection  consisted  of  a  sort  of  watery 
extract  made  from  the  testicles  of  animals. 
Afterwards  preparations  were  used  which  had 
been  more  carefully  prepared.  These  extracts 
are  employed  by  medical  men  under  the  name 
of  spermin  or  orchidin. 
126 


THE   DETERMINATION  OF  SEX 

In  a  similar  way  an  attempt  was  made  to 
obtain  extracts  and  pure  preparations  from 
the  ovaries  of  animals  (oophorin),  which  were 
to  be  used  in  the  same  manner. 


After  having  given  ourselves  the  trouble  to 
glance  through  the  long  series  of  different 
views  which  have  existed  concerning  the  ori- 
gin of  sex,  we  are  struck  with  the  fact,  that 
scarcely  a  single  objective  observation  has 
been  made  that  could  lead  to  a  positive  re- 
sult in  the  development  of  sex  in  the  new- 
born. Out  of  all  these  theories,  however,  one 
hypothesis  does  seem  to  be  tenable,  and  to 
that  we  shall  find  ourselves  compelled  to  give 
our  adhesion  here,  after  having  set  forth  the 
detailed  explanations  which  shall  presently  fol- 
low. Now,  we  were  not  led  to  the  recogni- 
tion of  the  truth  of  this  teaching  by  previ- 
ously assumed  theories.  On  the  contrary,  it 
was  after  we  had  completed  our  experiments, 
127 


SCHENK'S    THEORY 

and  had  been  led  by  them  to  positive  results, 
that  we  found  ourselves  compelled,  in  order 
to  find  an  explanation  of  the  whole  process, 
to  fall  back  upon  the  theory  of  cross-heredity 
of  sex,  and  to  place  it,  by  our  own  experi- 
ence, upon  firmer  foundations.  It  must  be 
briefly  remarked  here  that  the  literature  of 
this  subject  is  very  extensive,  and  to  trace 
out  all  the  literary  results  would  lead  us  too 
far.  For  which  reason  I  have  limited  myself 
to  the  actual  facts. 


In  order  to  enter  more  fully  into  our  theory, 
it  will  in  the  first  place  be  necessary  to  turn 
our  attention  to  the  products  of  excretion 
which  are  eliminated  from  the  bodies  of  ani- 
mals, in  a  more  or  less  solid,  fluid,  or  gaseous 
form,  as  the  results  of  the  transformations  of 
matter  which  have  taken  place  in  the  bodies 
of  the  animals.  The  chemical  constituents  of 
the  evacuations  are  either  such  as  it  has  not 
been  possible  to  convert  to  use  in  the  body, 
128 


THE   DETERMINATION  OF  SEX 

or  such  as  are  evacuated  as  the  final  product 
of  the  oxidation  which  has  been  effected  in 
the  body  by  the  process  of  combustion. 

Of  these  the  former  are  evacuated  from  the 
body  as  so  much  inert  matter  which  has  not 
been  affected  by  the  digestive  juice,  nor  al- 
tered in  any  other  way.  The  latter  are  given 
off  from  the  animal's  body  in  various  states 
of  oxidation  in  the  urine,  sweat,  or  dung,  or 
else  in  a  gaseous  form  by  the  lungs. 

A  great  number  of  the  substances  which 
have  been  hitherto  exactly  examined  are  se- 
creted by  the  kidneys  and  appear  in  the  urine. 
In  this  fluid  are  found  nitrogenous  products 
of  secretion,  others  free  from  nitrogen,  and 
inorganic  substances. 

Amongst  the  substances  free  from  nitrogen, 
I  found  myself  prompted  more  particularly  to 
select  as  an  object  of  my  attention  the  carbo- 
hydrate (sugar)  found  in  the  urine.  Three 
groups  of  closely  connected  compounds  are 
reckoned  amongst  the  carbo-hydrates.  They 

9  129 


SCHENK'S   THEORY 

consist  of  carbon,  hydrogen,  and  oxygen, 
which  contain  in  the  molecule  six,  or  a  mul- 
tiple of  six,  atoms  of  carbon.  The  hydrogen 
and  oxygen  are  in  the  same  proportion  as  in 
water.  (Arnold. ) 

The  three  groups  are  grape-sugar,  cane 
sugar,  and  cellulose.  In  the  urine  grape-sugar 
occurs  normally  among  the  products  of  excre- 
tion in  inconsiderable  quantities.  Under  ex- 
ceptional circumstances,  in  cases  of  polyuria, 
inosite  can  occur.  (H.  Voll,  Neumeister.)  In  ad- 
dition we  find  also  a  carbo-hydrate  mentioned 
by  E.  Luther  that  would  be  of  the  character 
of  dextrine,  and  probably  owes  its  existence  to 
the  secretive  activity  of  the  urinary  bladder. 

Upon  boiling  the  urine  with  mineral  acids 
we  obtain  substances  which  separate  as  brown 
flakes.  We  denote  these  <(  humin-substances )} 
(Huminsubstanzen,  Udransky,  Salkowski).  In 
addition  to  these  must  be  enumerated  animal 
gum,  isomaltose,  pentaglycoses,  laevo-rotary 
sugar,  the  conjugate  glycuronic  acids,  etc.  In 

130 


THE   DETERMINATION  OF  SEX 

conclusion,  the  occurrence  of  milk-sugar  must 
be  mentioned,  which  appears  in  the  last  days 
of  pregnancy.  The  last-mentioned  substances 
occur  in  very  insignificant  quantities,  and  are 
not  to  be  enumerated  among  the  ordinary 
constituent  parts  of  the  urine. 


The  carbo-hydrates  may  be,  in  many  re- 
spects, of  high  interest  for  the  activity  of  the 
organism  in  its  metabolism,  as  they  are  found 
amongst  the  products  of  excretion  only  as 
final  products  of  the  completed  transformation 
and  using-up  of  the  food. 

The  excretion  of  a  carbo-hydrate  in  the 
urine  can  be  interpreted  to  mean  that  the 
process  of  combustion  in  the  organism  in 
question  has  not  been  complete.  By  some 
agencies,  at  present  unknown  to  us,  the  effi- 
ciency of  the  organism  becomes  impaired  in 
such  a  way  that  it  does  not  fully  use  up  all 
combustible  substances. 

131 


SCHENK'S    THEORY 

A  number  of  substances  can  be  excreted 
from  the  body  which  are  capable  of  a  further 
process  of  oxidation  —  for  example,  until  they 
are  oxidized  into  carbonic  acid  and  water. 
The  heat  which  could  be  hereby  generated  is 
withdrawn  from  the  organism,  and  must  be 
procured  by  fresh  nourishment,  in  order  to 
replace  that  which  has  been  lost  by  an  im- 
perfect assimilation  of  the  food. 

One  substance  which  occurs  in  the  urine, 
about  which  much  has  been  written  by  vari- 
ous authors,  by  physiologists,  by  medical  men, 
and  by  chemists,  is  of  high  importance  for 
our  inquiry.  That  is  the  sugar  found  in  nor- 
mal urine. 

When  this  substance  occurs  in  the  human 
organism,  no  matter  in  how  small  a  quantity, 
its  presence  always  suggests  the  assumption 
that  it  ought  not  to  have  been  secreted  in  the 
form  of  grape-sugar.  For,  if  the  organism 
possessed  its  full  efficiency  to  deal  with  the 

132 


THE   DETERMINATION  OF  SEX 

necessary  quantity  of  food  taken,  then  one 
might  also  suppose  that  a  substance  such  as 
grape-sugar,  be  the  quantity  never  so  small, 
would  not  be  secreted  in  an  unaltered  form, 
but  must  be  further  used  up,  seeing  that  the 
sugar  would  be  decomposed,  oxidized,  in  short, 
burnt  up. 

The  imperfect  performance  of  an  operation 
of  this  kind  by  the  organism  is  not  to  be 
taken  for  a  symptom  of  pathological  processes. 
In  point  of  fact,  it  has  been  impossible  to 
recognize,  in  the  case  of  individuals  afflicted 
with  this  imperfection,  any  symptoms  of  proc- 
esses of  such  a  character  as  would  furnish 
the  remotest  occasion  for  the  appearance  of 
disease. 

When  small  quantities  of  saccharine  matter 
are  excreted,  derived  from  carbo-hydrates 
which  have  been  swallowed,  or,  on  the  other 
hand,  formed  within  the  human  body,  say 
from  albuminous  principles,  it  might  be 

133 


SCHENK'S   THEORY 

expected  that  this  excretion,  occurring  re- 
peatedly in  different  individuals,  ought  to  be 
regarded  as  a  normal  metabolic  process.  Such 
an  occurrence  must  be  interpreted,  in  fact, 
in  much  the  same  way  as  other  small  anoma- 
lies which  affect  the  organism,  whose  presence 
leads  to  no  further  consequences. 

But  our  attention  must  be  directed,  not  to 
the  sugar  alone,  but  to  a  number  of  other 
so-called  reducing  substances,  because  these, 
as  regards  certain  reactions,  resemble  grape- 
sugar,  and  have  to  be  distinguished  from  it. 


In  the  year  1858  my  highly-revered  mas- 
ter, E.  Brlicke,  drew  attention  to  the  pres- 
ence of  grape-sugar  in  normal  urine.  The 
foundation  of  the  theory  of  normal  glycosuria 
was  laid  by  his  obtaining  the  potassium  com- 
pound of  sugar  (sucker kali)  from  large  quan- 
tities of  urine.  His  theory  has  been  since 
much  elaborated,  and  a  great  deal  written 
both  for  and  against  it.  When  this  symptom 

134 


THE   DETERMINATION  OF  SEX 

in  the  urine  reaches  a  certain  proportion  per 
cent.,  the  condition  .of  the  individual  must  be 
described  as  diseased. 

If  we  apply  qualitative  chemical  tests  for 
sugar,  we  soon  find  that  they  are  disturbed 
by  a  number  of  reducing  substances  which 
exist  in  the  urine,  and  it  is  often  difficult  to 
determine  whether  the  processes  used  to  dis- 
cover the  sugar  do  not  produce  more  reduc- 
ing substances  than  the  sugar  itself. 

Bence-Jones  agrees  with  Briicke's  opinion 
respecting  the  presence  of  sugar  in  normal 
urine,  and  insists  upon  its  power  to  rotate 
the  plane  of  polarization  to  the  right.  More 
recent  authors,  Ivanof,  Huizinga,  Pavy,  Abe- 
les,  have  stated  this  fact  in  different  ways, 
and  it  yet  remains  to  be  verified.  The  fact 
existed,  but  not  without  meeting  with  con- 
tradiction. Maly,  Seegen,  Friedlander,  and 
many  others  sought  to  oppose  the  view. 

Although  in  many  cases  with  the  commonly 
used  reactions  it  is  impossible  to  demonstrate 

135 


SCHENK'S    THEORY 

the  presence  of  sugar  in  samples  of  urine, 
nevertheless,  the  sugar  has  been  isolated  in 
considerable  quantities,  by  means  of  precipi- 
tation with  acetate  of  lead  and  ammonia,  and 
by  subsequent  decomposition  of  the  precipi- 
tate with  sulphuretted  hydrogen  (E.  Ludwig), 
after  which  it  has  been  successfully  tested 
and  recognized  by  characteristic  reactions. 


We  shall  here  concern  ourselves  principally 
with  the  appearance  or  the  increase  of  the 
sugar,  so  far  as  its  presence  according  to  the 
views  hitherto  held  is  normal. 

We  are  acquainted  with  a  so-called  alimen- 
tary glycosuria,  which  is  occasioned  by  this, 
that  the  individual  in  question,  after  having 
eaten  an  excessive  quantity  of  sugar,  easily 
recognizes  an  increase  of  the  quantity  of 
sugar  in  the  urine.  But  there  are  also  indi- 
viduals, who,  though  they  may  have  eaten  a 
very  large  quantity  of  sugar,  cannot  afterwards 
136 


THE   DETERMINATION  OF  SEX 

discover  a  trace  of  it  in  the  urine.     In  these 
cases  complete  combustion  has  taken  place. 

But  here  we  must  also  next  direct  our  at- 
tention to  the  fact  that  there  are  persons 
who,  in  the  digestion  of  their  food  under  all 
circumstances,  excrete  sugar,  though  perhaps 
in  very  small  quantities.  Others,  after  eating 
proportionately  much  larger  quantities,  ex- 
crete no  perceptible  sugar  in  the  urine. 
Hoppe-Seyler,  after  having  eaten  225  grammes 
of  sugar,  could  find  no  trace  of  it  in  his 
urine.  (Moritz.)  Frerichs  admits  exceptions, 
and  relates  that  in  the  case  of  two  men  he 
could  always  discover  sugar  in  the  urine 
after  they  had  eaten  sugar,  although  he  con- 
sidered both  healthy.  Then  we  find  special- 
ists like  Budge,  C.  Schmidt,  Hosier,  Schiff, 
Vogel,  C.  Ludwig,  Voit,  etc.,  who  admit,  after 
their  experiments  with  men  and  beasts,  an 
artificial  glycosuria,  which  is  normal.  Seegen, 
after  feeding  dogs  with  cane  sugar,  found  in- 
verted sugar  (invert zucker)  in  the  urine.  The 

137 


SCHENK'S    THEORY 

sugar  which  he  was  able  to  identify  was  of 
two  kinds,  one  of  them  turning  the  polariza- 
tion plane  to  the  right,  and  the  other  turning 
it  to  the  left. 

Experiments  with  champagnes,  various 
other  wines  and  sweetmeats,  which  contain 
great  quantities  of  sugar,  gave  as  a  regular 
result  perceptible  sugar  in  the  urine  of  many 
individuals.  As  a  consequence  of  greater 
quantities  being  taken,  an  excessive  glycosuria 
set  in.  Its  duration  depended  upon  the  oc- 
casioning causes  alone.  On  their  removal, 
the  quantity  of  sugar  either  returned  to  a 
minimum  or  entirely  disappeared 


The  presence  of  sugar  in  normal  human 
urine  is  therefore  possibly  in  accordance  with 
all  the  above-mentioned  observations.  This 
fact  must  be  considered  a  physiological  axiom 
as  regards  the  constituents  of  normal  urine. 
The  quantity  of  sugar  contained  can  be 

138 


THE   DETERMINATION  OF  SEX 

increased  by  a  condition  of  alimentary  glyco- 
suria.  But,  when  there  is  no  such  artificial 
cause,  and  yet  the  sugar  is  recognizable, 
without  the  ordinary  regime  of  life  being 
altered,  still  its  presence  is  no  symptom  of 
a  pathological  process  going  on.  Even  the 
continuation  of  the  insignificant  excretion 
of  sugar,  when  it  continues  for  many  years, 
appears  to  exercise  no  influence  over  the 
health.  But  as  one  finds  many  individuals  in 
^vhose  urine  not  even  the  minimum  quantity 
of  sugar  is  discoverable,  it  seems  not  improb- 
able that  in  a  perfectly  normal  condition  of 
the  organism  it  is  possible  for  many  individuals 
completely  to  burn  up  the  whole  of  the  carbo- 
hydrates either  taken  into  the  organism  or 
formed  within  it.  Such  persons,  in  conse- 
quence of  their  metabolism  being  normal, 
are  able  to  carry  out  the  process  of  combus- 
tion to  the  full,  and  their  excretions  are  of 
such  a  nature  as  should  represent  the  nor- 
mal processes. 

139 


SCHENK'S    THEORY 

But,  if  this  condition  of  the  excretions  can- 
not be  attained  in  a  given  individual  in  the 
desired  degree,  the  organism  is  suffering  from 
an  imperfection  that  occurs  in  a  normal  man- 
ner (an  excretion  of  sugar)  to  a  certain  de- 
gree and  extent,  such  as  the  physiological 
potentialities  of  a  living  organism  permit. 

In  one  connection  only,  in  which  it  afforded 
me  practical  assistance  for  my  observations, 
this  question  has  not  yet  been  fully  eluci- 
dated. Sex  had  not  been  taken  into  con- 
sideration during  the  examination  of  the 
excretion  of  sugar  within  normal  physiolog- 
ical bounds.  Whilst  I  was  looking  through 
the  experiments  of  the  specialists  whom  I 
have  mentioned,  it  struck  me  that  most  of 
the  inquiries  respecting  the  presence  of  sugar 
in  normal  urine  had  been  made  in  the  case 
of  men  alone,  and  that,  so  far  as  regarded 
the  presence  of  sugar,  the  urine  of  the  hu- 
man female  had  been  little  observed,  and 
never  quantitatively  and  qualitatively  com- 

140 


THE   DETERMINATION   OF  SEX 

pared  with  that  of  man.  Nicolai  Ivanoff, 
in  his  dissertation  (Dorpat)  on  the  question 
of  glycosuria  in  the  case  of  pregnant  women, 
lying-in  women,  and  suckling  women,  arrived 
at  the  following  final  results :  <(  A  physiolog- 
ical glycosuria  in  the  case  of  the  pregnant,  or 
of  those  who  are  lying  in,  has,  so  far  as 
present  investigations  have  gone,  never  been 
established,  and  certainly  not  to  the  extent 
which  Blot  asserts.  Sugar  occurs  in  human 
urine  more  frequently  than  has  been  hitherto 
supposed,  but  absolutely  never  in  constant 
and  increased  quantities  in  that  of  pregnant 
and  lying-in  women. 

If,  however,  it  has  been  in  many  cases 
asserted  that  there  was  an  increased  quantity 
of  sugar  in  the  urine  of  pregnant  and  lying- 
in  women,  and  that  this  has  been  proved, 
these  statements  have  originated  from  mis- 
taking for  a  previously  developed  sugar  one 
which  has  during  the  experiments  come  into 
existence  from  the  action  of  alkalies  and 
141 


SCHENK'S    THEORY 

acids    on    an    extractive    substance    which   re- 
quires further  examination. 


For  the  detection  of  sugar  in  the  urine 
several  methods  exist,  which  are  more  or  less 
sensitive. 

If  we  mix  a  few  cubic  centimetres  of  urine 
with  an  equal  quantity  of  10  per  cent,  solu- 
tion of  caustic  potash,  and  warm  a  portion  of 
this  in  a  test-tube,  we  observe  that  the  fluid 
in  the  event  of  a  sensible  quantity  of  sugar 
being  present,  acquires  a  color  varying  from 
dark  yellow  to  yellowish  brown.  We  can 
most  easily  assure  ourselves  of  this  if  we 
warm  only  the  upper  part  of  the  fluid  con- 
tained in  the  test-tube,  whereupon  the  upper 
part  of  the  fluid  will  appear  darker  than  the 
rest. 

This  test  will  give  a  distinct  result  only  in 
presence  of  a  minimum  of  i  per  cent,  of 
sugar. 

142 


THE   DETERMINATION  OF  SEX 

A  much  more  sensitive  test  consists  in  the 
reduction  of  a  salt  of  bismuth  in  an  alkaline 
solution  of  urine  sugar.  This  test,  given  by 
Bottcher,  was  modified  in  the  following 
manner  by  Nylander.  Four  grammes  of 
Seignette  salts  are  dissolved  in  100  cubic 
centimetres  of  soda  lye  of  the  sp.  gr.  1.119, 
and  2  grammes  of  bismuth  subnitrite  are 
added  to  the  fluid  warmed  in  a  water- 
bath.  This  solution  represents  Nylander's 
reagent. 

In  order  to  use  the  test  we  mix  five  cubic 
centimetres  of  the  urine  to  be  examined 
(which,  if  possible,  ought  not  to  have  a  spe- 
cific gravity  higher  than  1.020)  with  0.5  cubic 
centimetre  of  Nylander's  reagent  in  a  test- 
tube.  The  mixture  is  now  boiled  for  two 
minutes.  If  more  than  0.5  per  cent,  of  sugar 
is  present  in  the  urine,  the  originally  white 
precipitate  of  earthy  phosphates  becomes  deep 
black;  with  0.05  per  cent,  of  sugar  it  shows 
a  clear,  brown  color. 

143 


SCHENK'S    THEORY 

If  this  test  is  not  the  most  sensitive  of  all, 
it  provides  us  with  a  process  for  recogniz- 
ing sugar  in  the  urine,  and  not  a  number 
of  other  reducing  substances  mixed  with  it. 
(Neumeister.) 

Amongst  the  various  tests  for  sugar  used 
in  practice,  that  of  Trommer  is  one  of  the 
most  common. 

We  mix  some  5  cubic  centimetres  of  urine 
with  an  equal  volume  of  10  per  cent,  solution 
of  potash  or  soda,  and  add  to  the  mixture, 
drop  by  drop,  a  10  per  cent,  solution  of  sul- 
phate of  copper,  so  long  as  the  resulting 
hydrated  oxide  of  copper  is  dissolved  by  the 
sugar. 

In  this  way  we  get,  according  to  the  quan- 
tity of  sugar  contained,  a  more  or  less  ultra- 
marine-blue fluid.  If  we  warm  this,  the 
result,  in  consequence  of  the  reducing  action, 
is  a  reddish-yellow  precipitate  of  hydrated 
suboxide  of  copper  which,  after  a  short  time, 
144 


THE   DETERMINATION  OF  SEX 

adheres  to  the  sides  of  the  test-tube,  some- 
what in  the  fashion  of  a  mirror. 

This  test  can  be  applied  fairly  simply,  and 
it  gives  good  results  in  presence  of  more  than 
0.5  per  cent,  of  sugar.  But  at  the  same  time 
we  cannot  use  it  to  detect  extremely  minute 
quantities  of  sugar  such  as  normally  occur  in 
human  urine,  because  the  urine,  as  we  have 
already  remarked,  contains  a  number  of  sub- 
stances which  reduce  alkaline  solutions  of 
copper. 

The  effect  of  these  substances  is  sometimes 
such  as  to  produce  the  illusion  that  from  0.3 
to  0.5  per  cent,  of  saccharine  matter  is  pres- 
ent. (Neumeister.) 

In  recent  times,  for  qualitative  and  quanti- 
tative investigation  of  the  grape-sugar,  much 
use  has  been  made  of  graduated  fermentation- 
tubes. 

For  this  experiment  we  mix  about  10  cubic 
centimetres  of  urine  with  a  small  quantity 
of  yeast  of  ascertained  weight,  and  fill  the 

10  145 


SCHENK'S    THEORY 

fermentation-tube  with  the  mixture.  After 
the  lapse  of  twenty-four  hours,  during  which 
the  whole  is  kept  in  an  incubator  at  a  tem- 
perature of  30°  centigrade,  all  the  grape-sugar 
will  be  completely  fermented. 

From  the  gaseous  fermentation-products  of 
the  grape-sugar,  which  rise  into  the  longer 
branch  of  the  U-tube,  and  consist  of  carbonic 
acid,  we  detect  the  presence  of  sugar  in  the 
urine. 

By  means  of  the  graduation  of  the  longer 
branch,  we  can  at  once  read  off  the  percent- 
age of  the  sugar.  This  test  is  sensitive 
enough  to  detect  0.05  per  cent,  of  sugar.  It 
is  useful  first  of  all  to  boil  the  urine  to  be 
tested,  in  order  to  remove  from  it  the  car- 
bonic acid  contained  in  solution.  It  is  also 
advantageous  to  acidify  the  urine,  so  that  the 
yeast  fungus  which  flourishes  more  easily  in 
the  acid  medium  may  overpower  any  gas-pro- 
ducing bacteria,  and  so  avoid  a  false  result. 

In    1884,    E.    Fischer   discovered  phenylhy- 

146 


THE   DETERMINATION   OF  SEX 

drazin,  and  pointed  out  the  fact  that  it  might 
be  used  as  a  valuable  reagent  for  the  sugar 
in  urine. 

This  preparation  has  the  characteristic  pe- 
culiarity of  forming  crystalline  compounds 
with  aldehydes  and  ketones.  These  crystals, 
in  the  cases  of  the  different  kinds  of  sugar, 
which,  as  is  known,  represent  the  aldehydes 
and  ketones,  respectively,  are  needle-shaped, 
of  a  yellow  color,  with  difficulty  soluble  in 
water,  have  a  high  melting-point,  and  are 
called  glycosazone. 

Jaksch  used  this  property  of  phenylhydrazin 
for  his  phenylhydrazin  test.  For  this  experi- 
ment he  dilutes  the  urine  with  an  equal  quan- 
tity of  distilled  water  in  a  test-tube,  and  adds 
twice  as  much  phenylhydrazin  hydrochloride 
as  can  be  taken  up  on  the  end  of  a  knife, 
and  double  that  quantity  of  sodium  acetate. 
The  mixture  is  well  shaken  together  and  left 
from  half  an  hour  to  an  hour  in  a  boiling 
water-bath. 

14? 


SCHENK'S   THEORY 

Then,  if  the  test-tube  and  its  contents  be 
slowly  cooled,  at  the  end  of  about  twelve 
hours  the  sediment  is  found  to  consist  partly 
of  spherical  resinous  lumps,  and  partly  of 
microscopical  tuft-shaped  crystals. 

These  crystals  are  nothing  else  than  gly- 
cosazone-compounds.  (Moritz.)  In  normal 
urine  this  reaction  is  very  often  observed  as 
distinctly  evident  as  if  we  had  to  do  with  a 
urine  containing  as  much  as  i  to  2  per  cent, 
of  sugar. 

In  reality  besides  the  extremely  minute 
traces  of  grape-sugar,  a  whole  number  of 
aldehydes  and  ketones  are  present  in  urine, 
which  can  form  phenylazone. 

Amidst  all  these  substances  those  which, 
according  to  the  investigations  of  Fliickiger 
chiefly  interfere  with  these  tests  are  the 
glycuronic  acid  compounds,  as  they  give 
crystals  of  the  same  form  in  the  course  of 
the  reaction.  Fliickiger  detected  these  com- 
pounds by  their  property  of  rotating  the 

148 


THE   DETERMINATION  OF  SEX 

polarization-plane  to  the  left,  and  reducing 
alkaline  solutions  of  copper  after  long  boil- 
ing. More  accurate  investigations  enabled 
him  to  identify  these  substances  with  ace- 
tone compounds. 

Moritz  recommends  the  following  method 
of  discovering  whether  we  have  to  deal  with 
grape-sugar,  glycuronic  acid  compounds,  or 
other  (azone)  crystal-forming  substances. 

Several  litres  of  normal  urine  are  precipi- 
tated with  lead  chloride  and  filtered;  the  fil- 
trate is  precipitated  with  ammonia  and  again 
filtered;  the  residue  on  the  filter  is  washed 
and  then  dried  on  a  clay  slab.  It  is  after 
this  decomposed  with  oxalic  acid,  mixed  with 
acetate  of  lead  in  excess,  and  the  filtrate  is 
deprived  of  its  lead  by  hydrosulphuric  acid. 
As  a  result  is  obtained  a  perfectly  clear  fluid 
to  which  the  phenylhydrazin  test  described 
above  is  applied. 

The  precipitate  obtained  is  filtered  off, 
149 


SCHENK'S    THEORY 

repeatedly  washed  with  chloroform  and  alco- 
hol, several  times  crystallized,  and  finally  the 
melting-point  of  the  needle-shaped  crystals, 
which  can  be  seen  with  the  naked  eye,  de- 
termined. If  sugar  is  present,  the  melting- 
point  of  the  crystals  will  be  at  a  temperature 
of  205°  centigrade.  If  the  melting-point  lies 
below  this  temperature,  we  have  to  do  with 
other  substances  (azones). 

Hence  it  appears  that  we  possess  in  the 
phenylhydrazin  test,  applied  in  the  manner 
above  described,  a  certain  method  of  detect- 
ing even  the  faintest  traces  of  sugar  in  the 
urine. 

Although  hitherto  it  has  been  often  ascer- 
tained that  sugar  was  present  in  normal  urine, 
that  was  demonstrated  only  by  the  other 
methods  with  which  we  have  been  hitherto 
acquainted,  and  not  by  means  of  the  phenyl- 
hydrazin test  in  the  manner  in  which  we  have 
explained  its  use.  This  seems  to  have  been 

150 


THE   DETERMINATION   OF  SEX 

the  reason  why  different  authors  have  not 
been  able  to  speak  unanimously  on  this  sub- 
ject.   

It  frequently  happens  that  the  sugar  is 
present  in  such  quantities  that  we  are  able 
to  observe  its  power  to  rotate  the  plane  of 
polarized  light. 

For  this  purpose  we  generally  use  Soleil- 
Ventzke's  penumbra-polarization  apparatus,  a 
description  of  which  will  be  found  in  the 
hand-books  on  the  subject. 

This  apparatus  suffices  to  investigate  the 
dextro-rotatory  and  laevo-rotatory  substances 
in  the  urine.  With  its  assistance  it  is  also 
possible  to  determine  the  quantity  of  sugar 
in  the  urine.  In  addition  for  the  determina- 
tion of  the  quantity  of  sugar  in  the  urine  a 
number  of  chemical  processes  can  be  em- 
ployed, such,  for  instance,  as  Fehling's  method 
with  Worm-Muller's  modification,  Knapp's 
method,  and  various  others. 

151 


SCHENK'S    THEORY 

If  we  add  to  normal  urine  a  dilute  solution 
of  potassium  permanganate  it  at  once  loses 
its  color.  From  this  we  perceive  that  the 
urine  contains  a  great  quantity  of  oxidizable 
or  so-called  reducing  substances. 

It  has  been  already  mentioned  that  Trom- 
mer's  test  gives  positive  results  after  pro- 
tracted boiling,  even  in  the  case  of  normal 
urine,  without  any  corresponding  quantity  of 
grape-sugar  being  present.  In  this  case  the 
reducing  substances  interfere  with  the  test  in 
consequence  of  their  tendency  to  become  oxi- 
dized. 

We  find  a  number  of  them  in  the  urine. 
Foremost  among  them  are  uric  acid,  creatin- 
ine,  and  the  coloring-matter.  Also  the  sub- 
stances mentioned  above  in  the  description  of 
the  carbo-hydrates  have  reducing  properties. 


Different  statements  have  been  made  as  to 
the  quantity  of  reducing  substances  existing 

152 


THE   DETERMINATION  OF  SEX 

in  the  urine.  According  to  Fliickiger  they 
form  from  0.15  to  0.25  per  cent.;  according 
to  Salkowski  an  average  of  0.4  per  cent.,  and 
according  to  Munk  an  average  of  0.3  per 
cent. 

Moritz  found  the  quantity  of  reducing  sub- 
stances range  between  2.93  and  4.1  grammes 
per  diem  in  a  grown  man.  His  investiga- 
tions were  made  with  the  collected  urine  of 
24  hours,  and  were  applied  to  that  of  men, 
women,  and  children.  The  result  showed  that 
men  always  excreted  a  greater  quantity  of 
reducing  substances  than  women  of  the  same 
age  who  used  the  same  food. 

The  quantity  of  these  substances  depends 
upon  the  food  taken.  An  increase  is  also 
possible  when  certain  benzoin  compounds  are 
taken  into  the  system.  Moritz  also  found 
that  the  ratio  of  the  quantity  of  reducing 
substances  to  the  food  was  a  constant,  which 
is  the  case  also  with  the  nitrogen  evacuated. 
An  increase  of  the  daily  excretion  of  reduc- 

153 


SCHENK'S    THEORY 

ing  substances  follows  the   free  use  of  albu- 
men. 

If,  in  the  case  of  an  ordinary  diet,  such  as 
men  take  in  youth,  the  body  performs  its 
labors  without  fatigue,  it  must  be  assumed 
that  the  several  food  stuffs  have  been  selected 
from  the  classes  of  albuminous  bodies,  carbo- 
hydrates, fats,  and  inorganic  elements  in  suit- 
able portions  and  are  provided  in  sufficient 
quantity. 

According  to  the  statements  of  Pettenkofer 
and  Voit  the  total  metabolism  is  greater  dur- 
ing labor  than  during  rest.  The  food  requi- 
site for  a  normal  grown  man  while  in  a  state 
of  rest  may  be  reckoned  at  30  units  of  heat 
for  each  kilogramme  of  weight.  In  the  case 
of  a  full-grown  working  man,  whose  weight 
was  70  kilogrammes,  the  necessary  food  rep- 
resented about  2,000  units  of  heat.  For  a 
person  whom  we,  following  Voit,  will  describe 
as  an  average  working  man,  the  requisite  food 

154 


THE   DETERMINATION  OF  SEX 

supply  consists  of  118  grammes  of  albumen, 
56  grammes  of  fat,  and  500  grammes  of 
carbo-hydrates,  equivalent  to  3,055  units  of 
heat  gross,  or  2,749  units  of  heat  net. 

As  a  woman  is  generally  smaller  than  a  man, 
and  the  weight  of  her  body  also  less  in  com- 
parison with  his,  and  her  labor  also  less  than 
that  of  a  man,  if  we  compare  men  and  women 
of  the  same  age,  it  is  obvious  that  in  her 
case  a  less  provision  of  force,  and  in  conse- 
quence less  food,  under  similar  circumstances, 
is  necessary  than  for  the  man.  Voit  assigns 
to  a  working  woman  a  food  supply  of  94 
grammes  albumen,  45  grammes  fat,  and  400 
grammes  carbo-hydrates,  which  correspond  to 
2,444  units  of  heat  gross,  and  2,200  units  of 
heat  net,  whilst  the  whole  of  the  food  taken 
by  an  average  working  man,  according  to 
Voit,  is  fixed  at  118  grammes  albumen,  56 
grammes  fat,  500  grammes  carbo-hydrates, 
equivalent  to  3,035  units  of  weight  gross,  and 
2,749  units  of  weight  net. 


SCHENK'S    THEORY 

Many  consider  that  the  quantity  of  albu- 
men is  placed  too  high.  For  this  reason 
Munk  assigns  a  lower  quantity  of  albumen 
for  the  food.  Yet  the  numbers  which  he 
gives  do  not  vary  much  from  those  of  Voit. 

In  youth  several  very  marked  differences 
appear  in  the  metabolism,  and  especially  in 
the  quantity  of  carbonic  acid  given  off,  and 
these  differences  appear  in  both  sexes.  (Tie- 
gerstedt. ) 

In  the  case  of  a  male  individual  from  four- 
teen to  nineteen,  the  quantity  of  carbonic 
acid  given  off  is  greater  than  in  the  case  of 
those  who  are  younger  or  older  of  the  same 
sex.  During  the  same  years,  also,  a  more 
rapid  increase  of  weight  takes  place,  and  a 
marked  increase  in  height.  This  shows  an 
increased  metabolism,  which  is  occasioned  by 
the  greater  addition  of  substance  to  the  body. 

In  the  case  of  the  female  individual  this 
increased  excretion  of  carbonic  acid  does  not 
occur  at  the  same  age.  A  girl  of  eleven 

156 


THE   DETERMINATION  OF  SEX 

gives  off  nearly  the  same  quantity  of  carbonic 
acid  as  a  grown  woman. 

The  quantity  of  carbonic  acid  given  off  by 
both  sexes  shows  that,  at  like  ages  and  under 
like  circumstances,  the  quantity  given  off  by 
men  in  their  younger  years  is  considerably 
greater  than  that  given  off  by  women. 

When  the  time  of  the  increase  of  the  body 
is  completed,  at  the  end  of  the  period  of 
growth,  with  both  sexes  there  is  little  differ- 
ence between  the  ingesta  and  the  egesta. 
The  difference  also  between  the  sexes  is 
much  less,  and  in  advanced  life  completely 
vanishes. 

It  will  be  seen  from  the  above  brief  state- 
ments respecting  metabolism  in  both  sexes 
that  a  difference  is  perceptible,  and  this 
implies  the  possibility  of  carrying  out  an 
attempt  to  express  that  difference  numer- 
ically. It  would  lead  us  too  far  were  we 
here  to  set  forth  all  the  consequences  con- 

157 


SCHENK'S    THEORY 

nected  with  these  facts  in  the  case  of  both 
sexes,  with  reference  to  growth,  physical  con- 
dition, etc.  These  are  sufficiently  known 
from  the  data  given  in  other  technical  works 
which  treat  of  the  characteristic  differences 
between  man  and  woman  in  different  ages. 

I  shall  here  call  attention  to  one  peculiarity 
only  of  the  human  female,  which  is  this,  that 
the  female  organism,  in  consequence  of  the 
less  abundant  formation  of  tissue,  is  on  a 
smaller  scale  than  that  of  the  male,  and  yet 
the  amount  of  sugar  given  off  in  the  urine 
is,  under  normal  circumstances,  nearly  the 
same  in  quantity  as  in  the  case  of  the  male. 

Where  there  is  less  abundant  formation  of 
tissue  there  must  be  evidently  less  strength. 
Consequently  a  weakness  in  the  organism, 
such  as  is  present  where  we  find  the  normal 
excretion  of  sugar,  will  have  a  more  marked 
influence  upon  the  work  done  than  a  greater 
weakness  of  the  same  kind  would  have  where 
the  mass  of  the  body  was  greater  and  the 

158 


THE  DETERMINATION  OF  SEX 

matter  taken  for  combustion  greater  also.  In 
other  words,  the  sugar  excreted  in  a  normal 
way  in  the  urine  of  the  man  does  not  indi- 
cate so  significant  a  loss  of  the  heat  produced 
by  combustion  as  it  indicates  in  the  case  of 
the  woman. 

When,  in  addition  to  this,  a  woman  is  in  the 
earlier  period  of  her  life,  at  which  time  an 
ovulation  takes  place  regularly  every  month, 
it  is  not  a  matter  of  indifference  whether  a 
good  and  complete  use  is  being  made  or  not 
being  made  of  the  matter  taken  as  nourish- 
ment. 

Also,  though  the  excretion  of  sugar  in  in- 
significant quantities  in  a  normal  way  is  not 
detrimental  to  the  whole  organism,  yet  it  ap- 
pears, as  we  shall  see  presently,  not  to  be  a 
matter  of  indifference  as  regards  the  ovum 
forming  itself  and  ripening  in  the  human  fe- 
male. 

Now,  if  we  take  further  into  consideration 
the  observation  which  I  made  many  years 

159 


SCHENK'S    THEORY 

ago,  that  sugar  often  occurs  in  the  urine  of 
women,  and  also  in  larger  quantities  than  we 
observe  in  the  case  of  men,  it  is  obvious  that 
this  symptom  ought  to  arrest  our  attention. 
Certainly  we  often  meet  with  female  urine 
which  shows  us  clearly  that  the  process  of 
combustion  in  the  organism  in  question  is 
being  perfectly  effected.  Practically  in  such 
urine  no  sugar  is  detected  by  the  reactions 
which  have  been  mentioned  above,  not  even 
by  the  phenylhydrazin  test.  Yet,  in  the  case 
of  many  of  these  women,  although  no  change 
has  been  made  in  the  diet,  sugar  is  found  in 
the  urine  temporarily  in  inconsiderable  quan- 
tities shortly  before  and  shortly  after  men- 
struation. The  methods  of  investigation  which 
we  have  applied  gave  at  these  epochs  a  posi- 
tive result. 

The  appearance  of  sugar  in  the  urine  does 
not  occur  only  amongst  women  of  the  upper 
classes,  who  enjoy  a  better  and  varied  diet, 

1 60 


THE   DETERMINATION  OF  SEX 

but  also  amongst  those  of  the  poorer  classes, 
who  are  obliged  to  subsist  chiefly  upon  veg- 
etable food. 

Indeed,  in  the  case  of  vegetarians  who  take 
concentrated  albuminous  substances  only  in 
the  form  in  which  they  occur  in  eggs,  and  get 
animal  fat  and  sugar  from  milk  alone,  the 
urine,  as  regards  the  occurrence  of  sugar,  is 
of  the  same  character  as  that  of  those  who 
do  not  adhere  to  vegetarianism.  Women,  who, 
in  other  climes,  are  not.  within  the  reach  of 
our  investigations,  might  also  be  included  in 
the  same  category  so  far  as  their  diet  is  con- 
cerned. 

It  follows  that  the  individual  does  not  ex- 
crete sugar  only  in  consequence  of  the  char- 
acter of  the  diet,  but  that  the  processes  of 
combustion  manifest  themselves  in  the  results 
derived  from  the  digestion  of  the  different 
nutriments. 

Now,  an  indispensable  condition  of  the  rip- 
ening of  the  ovum  in  the  female  organism  is 
ii  161 


SCHENK'S   THEORY 

that  the  metabolic  process  shall  be  normal. 
When  these  changes  are  being  effected  as 
perfectly  as  possible,  sugar  is  entirely  absent 
from  the  urine.  The  female  individual  may 
have  arranged  and  chosen  her  diet  from  the 
different  groups  of  food  in  any  conceivable 
way,  and  she  may  belong  to  this  or  that  class 
of  the  community,  but  the  metabolic  proc- 
esses—  that  is  to  say,  the  combustion  processes 
—  are,  nevertheless,  those  which  deserve  most 
attention  in  connection  with  the  development 
of  the  ovum. 

Ovulation  is  never  in  any  case  altogether 
independent  of  the  influences  of  diet  and 
metabolism.  In  those  cases  where  the  com- 
bustion is  of  such  a  kind  that  unoxidized  re- 
mains of  bodies  still  capable  of  producing 
heat  are  found  in  the  urine,  the  ovum  in 
process  of  development  in  the  human  female 
is  never  so  highly  developed  as  in  the  cases 
where  no  sugar,  or  at  least  no  recognizable 
trace  of  it,  can  be  found  in  the  urine. 
162 


THE   DETERMINATION  OF  SEX 

In  the  first  case  we  shall  have  not  only  a 
less  ripe  ovum,  but  very  likely  also  a  less  well- 
nourished  ovum.  An  ovum  of  this  sort  has 
not  so  fully  attained  to  all  the  characteristics 
and  powers  inherent  in  its  protoplasm,  and,  in  ") 
consequence,  seems  fitted  to  develop  only  a  fe- 
male individual.  5w  suck  anovum  the  several 
cell-products  of  the  ovum,  which  have  to  de- 
velop themselves  'into  the  future  embryo,  will 
be  arranged  for  the  growth  of  a  female.  Not 
only  will  female  organs  of  generation  be  de- 
veloped from  it,  but  also  all  the  elements  of 
the  future  individual  will  be  feminine. 

On  the  contrary,  if  in  the  mother-individual 
all  the  substances  developed  in,  or  taken  into, 
the  organism  undergo  combustion  in  such  a 
manner  that  no  sugar  is  found  in  the  urine, 
not  even  in  the  smallest  quantities,  then  an 
ovum  can  be  developed  such  as  is  required  to 
produce  a  male  individual.  Out  of  its  proto- 
plasm in  the  course  of  evolution  elements  form 
themselves,  whence  male  cells  are  developed, 
163 


SCffENICS   THEORY 

which  correspond  to  the  development  of  tissues 
and  forms  of  the  male  individual.  Some  of 
the  cells  —  viz.:  those  which  ultimately  become 
the  elements  for  the  continuation  of  the  species, 
are  planned  for  the  male  sex. 

It  follows  from  all  this  that  the  result  de- 
pends to  a  great  extent  both  upon  the  diet 
chosen,  and  upon  whether  it  has  been  rightly 
chosen  to  suit  the  organism,  whether  it  is 
possible  to  exert  such  an  influence  as  may  so 
support  the  ovum  in  its  maturation  that  in  its 
development  it  may  form  itself  into  a  male 
individual.  It  must  be  observed  in  advance 
that  such  an  influence  as  may  be  effective 
for  the  production  of  sex  must  not  be  applied 
to  an  already  fertilized  ovum,  but  must  be 
applied  to  an  ovum  in  development  before 
its  fertilization. 

Indeed,  it  is  even  of  greater  importance  to 
know  that  the  mother  individual  has  been  for 
,          a  considerable  period  anterior  to  the  fertiliza- 
tion of  the  ovum  provided  with  the  requisite 
164 


THE   DETERMINATION  OF  SEX 

food.  Care  must  also  be  taken  that  after 
conception  a  similar  befitting  diet  is  continued 
for  the  mother,  which  diet  should  resemble 
that  previously  provided. 


Of  what  sort  must  the  chosen  diet  be 
which  can  favor  the  ripening  of  the  ovum  ? 
Always  only  such  a  diet  as  can  so  modify  the 
process  of  food  assimilation  in  the  organism 
that  no  excretion  even  of  the  most  minute 
quantity  of  sugar  discoverable  by  the  appli- 
tion  of  the  phenylhydrazin  test  can  be  de- 
tected. 

The  quantity  of  sugar  is  small,  but  what 
has  to  be  taken  into  consideration  here  is  not 
so  much  the  amount  of  the  sugar,  as  the  fact 
that  this  substance  is  being  excreted. 

Now,  it  has  been  proved  by  experience  that 
when  in  an  organism  a  symptom  appears,  as 
the  evidence  of  disease,  in  the  form  of  a 
considerable  excretion  of  sugar  in  the  urine, 

165 


SCHENIfS   THEORY 

it  is  in  many  cases  possible,  by  the  means  of 
fitting  diet,  to  produce  a  diminution  of  the 
excretion  of  sugar,  either  bringing  it  down  to 
a  small  amount  or  causing  it  to  disappear 
altogether. 

Investigation  of  the  urine  according  to  rec- 
ognized methods  must  accompany  this  system 
of  diet,  and,  under  normal  circumstances, 
we  soon  meet  with  the  phenomenon,  at  which 
we  have  been  aiming  —  that  the  quantity  of 
sugar  has  diminished  to  a  no  longer  percept- 
ible amount.  When  this  has  been  attained, 
it  may  be  presumed  that,  by  a  further  perse- 
verance with  the  same  diet,  the  metabolism 
will  be  so  regulated  that,  if  no  pathological 
accident  supervenes,  the  excretion  of  sugar 
will  cease.  In  fact,  in  consequence  of  an 
alteration  of  diet  and  the  taking  of  no  ex- 
cessive quantities  of  starch  and  sugar,  the 
excretion  of  sugar  in  the  urine  ceases  for  a 
considerable  time,  and  only  makes  its  reap- 
pearance after  a  long  interval. 

1 66 


THE   DETERMINATION  OF  SEX 

When,  in  consequence  of  having  observed 
the  minute  normal  quantity  of  sugar  in  the 
urine,  my  attention  was  attracted  to  the  fact 
that  the  determination  of  the  future  sex  was 
connected  with  the  presence  of  this  sugar, 
my  endeavors  were  directed  to  exercising 
such  an  influence  over  its  presence  as  might 
enable  me  to  get  rid  of  it.  Experiments  with 
the  most  diverse  diets  gave  me  in  the  case 
of  women  most  remarkable  results.  In  this 
way  I  found  women,  using  an  almost  exclu- 
sively flesh  diet  (which  was,  of  course,  espe- 
cially rich  in  nitrogen),  whose  urine  showed 
greater  quantities  of  sugar  —  according  to  ap- 
proximate estimations  —  than  when  they  used 
a  diet  of  carbo-hydrates,  that  is,  sugar,  fatty 
substances,  alcohols,  etc.  Others,  again,  showed 
an  exactly  opposite  result.  In  many  cases  I 
did  not  succeed  in  getting  rid  of  the  normal 
sugar  in  the  urine;  in  others  it  disappeared 
soon  after  the  beginning  of  the  treatment.  It 
follows  that,  in  every  case  where  the  question 

167 


SCffENJCS   THEORY 

is  one  of  so  influencing  the  sex  that  a  male 
offspring  may  be  obtained,  the  very  first 
thing  to  be  determined  is  whether  the  normal 
quantity  of  sugar  is  present  in  the  woman's 
urine  or  not.  If  none  can  be  detected  after 
repeated  and  painstaking  search,  and  if  re- 
ducing substances  are  plentifully  present, 
we  do  not  require  to  arrange  the  diet,  but 
can  recommend  immediate  impregnation,  as 
every  probability  points  to  a  male  embryo. 
But  in  all  cases  where  the  normal  (( urine- 
sugar  }>  —  if  I  may  so  call  it  —  is  present, 
even  if  only  traces  of  it  are  to  be  found, 
it  will  then  be  our  task,  by  various  altera- 
tions of  diet,  to  discover  that  one  which 
seems  suited  to  the  organism  in  such  a  way 
that  it  will  occasion  the  disappearance  of 
every  trace  of  the  <(  urine-sugar. }>  In  these 
experiments  the  remarkable  phenomenon  is 
observable,  that  the  reducing  substances 
which  I  have  already  mentioned,  and 
amongst  these  especially  the  laevo-rotatory 
168 


THE   DETERMINATION  OF  SEX 

glycuronic   acid   compounds,   show  alterations 
in  respect  of  quantity. 


In  fact,  I  found  that  the  urine  of  most 
women  who  had  male  offspring  contained, 
during  the  first  months  of  pregnancy,  more 
reducing  substances  than  the  urine  of  women 
who  had  female  offspring.  It  is,  therefore, 
also  necessary  that  the  diet  should  not  only 
occasion  a  disappearance  of  the  normal  urine- 
sugar,  but  should  also  produce  an  increase  of 
the  reducing  substances.  This  end  can  be 
accomplished  certainly  also  by  the  use  of  dif- 
ferent medicines,  such  as  chloroform,  turpen- 
tine, salicylic  acid,  etc.  But,  apart  from  the 
fact  that  medicinal  influences  are  distinctly 
to  be  discouraged,  these  substances  do  not 
seem  to  produce  the  same  effects  as  diet. 
Besides,  it  is  still  a  question  of  what  kind 
these  efficient  substances  are.  And  another 
question  is  whether  they  are  themselves  ef- 
169 


SCHENK'S    THEORY 

fective.  It  will  be  sufficient  for  us  to  recog- 
nize them  as  a  symptom. 

It  is  known  that  the  male  sex  possesses  a 
distinctly  greater  amount  of  albumen  than  the 
female.  In  age  this  difference  disappears;  in 
youth  it  is  greater.  It  might  be  expected 
that  male  offspring  would  result,  in  conse- 
quence of  a  more  albuminous  diet,  by  which 
a  greater  increment  of  albumen  would  be 
made  possible;  the  thing,  however,  is  not 
quite  so  simple  as  this.  Investigations  in  va- 
rious cases  showed  me  that  women  in  whom 
an  increased  amount  of  albumen  could  be  de- 
tected, but  in  whom  either  sugar  was  present 
to  a  small  extent,  or,  on  the  other  hand,  only 
very  small  quantities  of  reducing  substances 
could  be  detected,  almost  always  had  female 
offspring. 

In  spite  of  many  endeavors  to  elucidate 
this  phenomenon,  I  was  forced  to  have  re- 
course to  the  symptoms  alone,  and  to  hope 
for  the  production  of  the  male  sex  only  from 

170 


THE   DETERMINATION  OF  SEX 

the  disappearance  of  the  sugar  and  the  in- 
crease of  the  reducing  substances.  Certainly, 
further  investigations  showed  that  the  same 
diet  which  was  the  most  favorable  to  the  pro- 
duction of  the  condition  which  I  have  named 
(the  disappearance  of  the  sugar  from  the  urine 
and  the  simultaneous  increase  of  the  reducing 
substances),  also  effected  the  best  albuminous 
increment  in  the  body.  Key's  statements 
teach  us  that  male  individuals  put  on  more 
albumen  than  females,  and  that  this  is  espe- 
cially the  case  during  the  period  of  growth. 
Very  likely  the  male  embryo  also  requires  a 
greater  amount  of  albumen  than  the  fe- 
male, in  the  same  way  as  this  difference 
exists  between  the  boy  and  girl. 


We  know  as  a  universal  rule  that  where 
there  is  rest  there  must  be  a  balance  of 
forces.  If  the  ovum,  the  accumulator  of  the 
balanced  forces  in  a  state  of  rest,  is  to  divide 

171 


SCHENK'S    THEORY 

itself  so  as  to  produce  in  this  way  the  future 
individual,  some  stimulant  impulse,  some 
energy  is  absolutely  necessary  to  disturb  the 
balance  of  forces,  and  to  induce  the  de- 
velopment of  the  cells.  This  impulse  may 
be  such  a  one  as  occasions  destruction.  But 
it  may  also  be  one  that  gives  occasion  to  new 
growth,  to  tissue  formation.  (W.  Haacke.) 
We  must  describe  this  impulse  as  functional, 
and  recognize  in  it  a  peculiarity  which  be- 
longs to  the  organic  world  alone,  the  vege- 
table and  animal  kingdom.  Every  movement, 
every  use  of  an  organ,  may  serve  as  a  stimu- 
lant impulse,  and  contribute  to  its  develop- 
ment. Thus  we  find,  in  the  case  of  great 
thinkers  and  poets,  of  celebrated  generals, 
etc.,  a  powerfully  developed  brain.  Oarsmen, 
gymnasts,  and  swimmers  have  far  stronger 
muscles  than  men  who  follow  less  fatiguing 
callings.  In  all  these  cases  there  are  impulses 
leading  to  increased  growth  of  the  organs.  In 
the  growth  of  the  fertilized  ovum  we  have  to 

172 


THE   DETERMINATION  OF  SEX 

deal  again  with  a  phenomenon  of  impulse,  a 
part  of  which  is  the  property  of  the  ovum 
itself,  a  part,  however,  also  dependent  upon 
external  influences.  We  call  the  former 
autoplastic,  the  latter  xenoplastic  impulse. 
(Haacke.)  It  is  easy  to  understand  that  a 
purely  autoplastic  development  (eine  reine 
Autoplasie,  a  pure  autoplasia)  cannot  exist. 
Out  of  an  ovum  alone,  without  the  agency  of 
new  impulses,  without  the  taking  up  of  new 
matter,  no  new  individual  could  develop. 


The  stomach  furnishes  the  gastric  juice.  It 
is  stimulated  to  do  so  by  the  food.  The  food 
is  digested,  undergoes  absorption  in  the  intes- 
tine, and  becomes  lymph.  Blood  is  formed. 
The  blood  passes  through  the  several  organs 
and  tissues,  nourishes  them,  and  replaces  the 
substances  used  up  by  work.  As  soon,  there- 
fore, as  the  stomach  and  intestine,  with  the 
intestinal  glands,  fail  in  their  functions,  all 


SCHENK'S    THEORY 

the  organs,  which  stand  in  physical  relation 
with  them,  suffer;  because  they  are  con- 
stantly during  their  work  consuming  matter, 
and  are  now  receiving  no  fresh  supplies. 
The  case  of  the  other  juices  of  the  body  is 
the  same.  The  thyroid  glands  supply  the 
body  with  a  principle  without  which  a  per- 
son cannot  be  in  a  normal  condition.  Simi- 
larly the  testicles,  as  glands,  supply  the  body 
with  a  principle  the  want  of  which  gives  a 
man  distinctly  female  qualities,  as  we  per- 
ceive in  the  case  of  eunuchs. 


There  is  no  doubt  that  the  males  and 
females  of  a  race  of  animals  develop  out  of 
the  same  germinal-matter.  Its  development 
depends  upon  two  important  factors,  the  im- 
pulse, and  the  capacity  to  take  up  matter 
conditioned  thereby.  By  taking  up  matter 
the  substance  of  the  newly  developed  cells  is 
increased,  and  this  in  turn  prompts  them  to 


THE   DETERMINATION  OF  SEX 

repeated  division,  until  at  last  an  organ  is 
developed.  The  new  organ  again  furnishes 
new  impulses,  and  so  influences  the  develop- 
ment of  other  organs.  The  impulses  are  of 
themselves  physical  and  chemical.  (Haacke.) 
In  the  ovule  and  the  embryo  the  impulses 
are  what  chiefly  bring  about  new  growth. 
These  impulses  the  ovum  receives  from  the 
mother  whose  product  it  is.  Now,  as  of  the 
most  different  impulses  now  one  and  now 
another  comes  to  the  front,  the  embryo 
will  acquire  at  this  time  rather  these  quali- 
ties, and  at  that  time  those.  The  impulse 
will  occasion  now  a  greater  addition  of 
matter  to  this  organ,  and  now  a  greater 
addition  of  matter  to  that.  According  to 
observations  made  up  to  the  present  time, 
there  is  hardly  any  doubt  that  the  develop- 
ment of  the  organs  of  sex  requires  an  im- 
pulse as  does  the  development  of  all  the 
other  organs.  These  sex-determining  im- 
pulses originate,  like  the  other  development- 

175 


SCHENK'S    THEORY 

determining  influences,  from  the  mother, 
since  it  is  she  that  supplies  to  the  embryo,  as 
agencies  of  impulse,  the  juices  derived  from 
the  food  which  she  has  taken.  In  addition 
to  these,  the  embryo  receives  also  from  the 
mother  such  products  as  are  required  for 
the  growth  that  follows  the  impulse.  If  the 
mother  gives  the  child  no  material  for  growth 
and  no  impulse,  then  the  child,  since  it  is  de- 
pendent upon  the  mother,  must  perish.  Now, 
according  as  a  developing  ovum  or  an  em- 
bryo either  receives  the  juice,  the  means  of 
impulse,  for  the  acquisition  of  the  male  sex, 
or  for  the  acquisition  of  the  female  sex,  so 
will  a  male  or  a  female  result. 


Of  what  kind  the  means  of  impulse  are, 
the  juices  are,  which  occasion  this  I  do  not 
know.  I  can  only  supply  the  conditions  req- 
uisite for  them;  I  can  see  only  whether  they 
are  present.  And  so  I  again  come  back  to 

176 


THE   DETERMINATION  OF  SEX 

this,  that  we  may  expect  a  male  individual 
from  the  ovum  when  the  juices  are  developed 
which  serve  as  a  functional  means  of  impulse 
for  the  male  sex.  These  juices  can  come 
into  existence  in  the  organism  under  the 
most  different  circumstances.  But  they  cer- 
tainly do  come  into  existence,  if  we  can  so 
feed  the  mother  that  we  cannot  find  in  her 
urine  even  the  faintest  trace  of  sugar,  but 
instead  of  it  an  increased  excretion  of  re- 
ducing substances,  accompanied  by  a  relatively 
high  exchange  of  nitrogenous  substances.  These 
facts  can,  therefore,  serve  us  only  as  a  symp- 
tom of  processes  taking  place  in  the  organ- 
ism. In  consequence  our  task  will  be  to  fol- 
low up  in  the  various  cases  the  conditions  of 
this  symptom,  in  order  that  we  may  try  so  to 
feed  the  mother  individual  that  she  may  attain 
to  giving  the  effective  impulse ;  and  this  we 
have  certainly  accomplished  by  the  increased 
excretion  of  the  reducing  substances  and  the 
disappearance  of  the  normal  urine-sugar. 

12  I77 


SCHENK'S    THEORY 

When  we  have  brought  a  woman  into  such 
a  condition  that  she  excretes  no  sugar,  and 
by  the  continuation  of  the  same  diet  keep 
her  permanently  in  that  condition,  the  ovule 
which  is  being  developed  in  her  organism 
will  develop  itself  correspondingly.  Also 
with  this  diet  the  different  qualities  of  the 
organism  may  not  be  altogether  without  in- 
fluence on  the  course  of  the  ovum's  develop- 
ment. 

In  many  cases  the  quantity  of  sugar  in  the 
urine  excreted  does  not  diminish.  The  most 
different  kinds  of  diet  may  be  tried,  and  yet 
the  phenylhydrazin  test  will  always  show  the 
presence  of  sugar.  Individuals  of  this  sort 
exhibit  a  certain  obstinacy  in  resisting  the 
attempt  to  procure  an  alteration  of  the  metab- 
olism. In  such  cases  no  influence  has  been 
exerted  over  the  development  of  the  ovum. 

In  these  experiments  which  are  made  with 
the  mother,  not  only  is  the  ovum  influenced 
which  is  being  developed  for  fertilization  in 

178 


THE   DETERMINATION  OF  SEX 

the  maternal  organism,  but  it  is  also  possi- 
ble for  the  mother  herself,  in  consequence 
of  the  alteration  of  diet,  to  experience  many 
changes  with  regard  to  the  physical  pecul- 
iarities of  the  elements  which  compose  her 
body. 

The  treatment  may  prove  highly  beneficial 
to  the  mother  herself,  so  that  not  ovulation 
alone  is  subjected  to  an  alteration,  but  the 
activity  of  the  processes  of  the  tissues  of  the 
other  organs  of  the  body  may  be  also  simul- 
taneously in  some  way  changed.  And  here 
may  come  into  consideration  many  other  fac- 
tors which  may  produce  a  particular  fitness 
for  procreation  and  for  the  development  of 
the  ovum,  and,  if  they  once  make  themselves 
felt,  may  be  of  the  greatest  advantage  to  the 
mother. 

The  formation  of  the  insignificant  quantity 
of  sugar  in  the  body  goes  on  of  itself  regu- 
larly, without  it  being  possible  to  perceive 
any  consequent  striking  alterations  in  the 
179 


SCHENK'S   THEORY 

organism.  The  manner  in  which  sugar  is 
formed  in  the  body  under  normal  conditions 
has  in  recent  years  been  thus  explained. 

The  sugar  contained  in  the  blood  in  healthy 
persons  is  reckoned  as  not  higher  than  about 
0.15  per  cent.  In  those  who  suffer  from  dia- 
betes it  may  rise  to  0.44  per  cent.  If  sugar 
is  present  in  the  blood,  that  it  passes  thence 
into  the  urine  can  be  easily  explained,  seeing 
that  the  excreted  products  of  decomposition 
from  the  blood  pass  into  the  urine.  Thus  the 
sugar  results  from  a  portion  of  the  food  which 
is  transformed  into  sugar,  and  so  passes  into 
the  portal  vein.  (Strlimpell.) 

There  exists  also  in  the  liver  and  muscles 
a  non-nitrogenous  substance,  glycogen,  which 
is  detected  also  in  other  organs.  This  gly- 
cogen probably  arises  partly  from  the  carbo- 
hydrates of  the  food,  but  certainly  from  the 
albuminous  substances  taken  with  the  food, 
which,  when  broken  up,  separate  into  nitrog- 
enous products  and  glycogen. 

180 


THE   DETERMINATION  OF  SEX 

When  the  glycogen  is  once  formed,  we 
may  regard  it  as  an  intermediate  substance 
which  is  changed  into  sugar,  probably  by  a 
saccharine  fermentation,  and  then  can  reach 
the  blood.  How  glycogen  is  transformed 
into  sugar  within  the  organism  is  unknown. 
Normally  occurring  sugar  results  from  gly- 
cogen. 


181 


CHAPTER  IV 

WHEN,  years  ago,  my  attention  was  first 
attracted  by  the  idea  that,  for  the  solution  of 
our  problem,  we  ought  to  turn  our  attention 
to  the  sugar  in  normal  urine,  no  very  exact 
tests  for  sugar  were  possible.  The  reactions 
were  not  very  sensitive,  the  fact  being  that 
the  surest  evidence  of  the  presence  of  sugar 
was  obtained  not  from  the  reduction  proc- 
esses but  from  the  method  used  by  Briicker 
for  preparing  a  potassium  compound  of  sugar. 

Every  investigation  which  I  undertook  in 
his  times  for  the  confirmation  of  my  theory 
was  very  arduous.  The  few  cases  which  I 
at  first  had  under  observation  presented  for- 
midable difficulties.  The  occasion  of  my  first 
turning  my  attention  to  sugar  in  the  urine 
was  a  case  of  a  woman  who  had  borne  five 
182 


THE   DETERMINATION   OF  SEX 

children,  and,  after  violent  and  continuous 
mental  excitement,  was  suddenly  seized  with 
diabetes  mellitus.  I  frequently  examined  her 
urine,  and  always  found  an  abnormal  amount 
of  sugar.  She  had  twice  given  birth  to  chil- 
dren whilst  suffering  from  diabetes,  and  on 
each  occasion  the  child  was  a  female.  This 
fact  struck  me,  because  previously,  whilst  she 
was  strong  and  well,  she  had  borne  sons  only. 
But,  on  the  appearance  of  the  disease  men- 
tioned, she  had  two  daughters  in  succession, 
of  whom  the  first  one  lived  and  the  other 
was  still  born. 

I  numbered  amongst  my  acquaintances  a 
family,  of  whom,  in  the  course  of  years,  I 
was  acquainted  with  the  grandmother,  a 
daughter,  and  two  grand-daughters.  The 
grandmother  had,  including  the  third  gener- 
ation, fifteen  descendants,  of  whom  twelve 
were  girls  and  three  were  boys.  Two  of  the 
boys  were  the  sons  of  the  grandmother,  and 
the  first  two  children  she  had  borne.  She 

183 


SCHENK'S   THEORY 

was  under  medical  treatment,  and  the  analy- 
sis of  the  urine  showed  a  considerable  quan- 
tity of  sugar.  She  had  six  daughters.  One 
of  these  daughters,  who  survived  the  others, 
had  five  children,  amongst  them  one  boy, 
who  soon  died. 

Two  of  the  grand-daughters  of  this  family 
became  mothers,  each  bearing  one  daugh- 
ter. I  had  the  opportunity  of  examining 
the  urine  of  all  the  mothers  of  this  family, 
and  always  found  sugar  in  it.  Sometimes 
the  saccharine  contents  reached  a  remark- 
able quantity,  and  yet  were  not  such  as 
could  be  diagnosed  to  indicate  an  unhealthy 
condition. 

Amongst  the  acquaintances  of  my  youth 
was  a  young  lady  of  good  family.  Carefully 
reared,  she  was,  as  a  child,  too  much  shel- 
tered from  the  influences  of  the  open  air,  and 
in  later  years  much  imprisoned  in-doors  by 
hard  study  in  different  branches  of  art  and 
science.  As  a  young  lady  she  was  fairly 

184 


THE   DETERMINATION  OF  SEX 

tall  and  well  nourished,  but  pale  and  pos- 
sessed of  little  color. 

It  happened  that  I  had  an  opportunity  of 
examining  this  young  lady's  urine.  As  I  found 
a  considerable  quantity  of  sugar,  I  was  led 
to  the  conclusion  that  the  girl  (she  was  en- 
gaged) would  have  principally  female  offspring. 

Many  years  had  elapsed.  The  young  lady 
had  ripened  into  a  stately  matron,  and  told 
me  that  she  had  the  happiness  to  be  the 
mother  of  five  daughters  and  a  son.  I  am 
altogether  without  the  statistics  necessary  to 
deduce  from  a  great  number  of  similar  cases 
the  average  relative  number  of  the  sexes 
born  of  women  suffering  from  diabetes.  But 
this  must  be  pointed  out,  that,  notwithstand- 
ing the  high  percentage  of  sugar  excreted 
in  the  case  of  women  suffering  from  pro- 
nounced diabetes,  female  offspring  do  not 
necessarily  always  appear.  They  will  prob- 
ably be  in  a  very  striking  majority  when 
compared  with  the  males,  but  the  complete 

185 


SCHENK'S    THEORY 

disappearance  of  the  male  sex  is  not  to  be 
anticipated,  because  male  individuals,  though 
in  the  minority,  can  appear.  And  this  was 
to  be  anticipated,  seeing  that  in  the  so-called 
slighter  cases  of  this  complaint  the  abnormal 
metabolism  can  be  sensibly  improved  by  at- 
tention to  diet. 


Diabetes  amongst  women  has  a  marked 
influence  upon  the  functions  of  the  sexual 
organs.  Thus,  for  example,  the  menses  cease, 
a  condition  which,  according  to  gynaecologists, 
is  occasioned  by  an  abnormal  condition  of 
the  womb  and  of  the  ovaries  which  be- 
come atrophied.  (Schauta )  On  the  other 
hand,  diabetes  may  also  result  from  diseases 
of  the  reproductive  organs.  (Imlach.)  When 
the  cause  of  the  complaint  is  removed  from 
the  female  genitals  the  sugar  also  disappears 
from  the  urine. 

From  both  of  these  facts,  which  rest  upon 
medical  observation,  it  follows  that  the  excre- 

186 


THE  DETERMINATION  OF  SEX 

tion  of  sugar  has  some  definite  connection 
with  the  processes  at  work  in  the  female 
generative  organs.  In  the  cases  when  the  ex- 
cretion of  sugar  continues  for  a  considerable 
time,  it  is  of  greater  significance,  and  indi- 
cates chronic  derangement  of  the  metabolism, 
in  connection  with  which  a  serious  change 
comes  over  the  internal  organs  of  generation. 


Now,  if  there  is  a  possibility  that  disturb- 
ances so  extensive  can  be  set  up  in  the  fe- 
male genital  tract  when  there  is  an  excre- 
tion of  sugar,  it  is  also  very  possible  that 
certain  modifications  may  be  produced  by 
a  small  constant  excretion  of  sugar.  These 
changes  can  show  themselves  in  the  ovum  to 
this  extent,  that  they  may  be  of  considerable 
significance  and  not  without  influence  upon 
the  development  of  sex. 

Women  who  suffer  from  pronounced  dia- 
betes frequently  miscarry.  In  what  way  the 

187 


SCHENK'S    THEORY 

disease  influences  ovulation  I  cannot  here  dis- 
cuss. 

The  connection  of  the  development  of  sex 
with  an  imperfect  physiological  combustion  of 
the  food  can  only  be  considered  as  demon- 
strated, if  it  is  possible,  by  means  of  certain 
exact  experiments  in  this  direction  to  reach 
results  which  incontestably  make  for  the  pos- 
sibility of  influencing  sex.  Cases  of  this  kind, 
in  which  the  work  of  observation  was  con- 
ducted by  myself  alone,  and  in  families  closely 
connected  with  me,  where  there  were  excep- 
tional wishes  in  this  direction,  I  shall  mention 
presently. 

Most  striking  of  all  are  the  cases  where 
a  number  of  daughters  have  come  into  the 
world  one  after  another  as  the  results  of  a 
marriage. 

The  condition  of  a  woman  in  a  well-regu- 
lated married  state,  when,  as  we  will  sup- 
pose, five  or  six  girls  are  born,  one  after 

188 


THE   DETERMINATION   OF  SEX 

another,  must  be  considered  to  be  of  a  kind 
that  departs  more  or  less  from  the  normal. 
The  human  female,  if  we  regard  the  general 
statistical  data,  ought  to  bring  forth  approxi- 
mately the  same  number  of  male  and  female 
individuals.  If  we  find  so  remarkable  an  ex- 
cess in  the  direction  either  of  males  or  fe- 
males, that  six  or  seven  of  the  same  sex 
follow  one  another,  there  must  be  a  reason 
for  this.  In  my  opinion  that  cause  is  now 
to  be  ascertained  only  from  the  results  of 
analysis  of  the  urine  for  sugar,  mentioned 
above. 

In  the  cases  where  we  have  to  deal  with 
an  excessive  predominance  of  female  off- 
spring, Trommer's  test  will  show  us  the  pres- 
ence of  sugar.  But  it  is  safest,  as  I  have  al- 
ready said,  to  use  the  phenylhydrazin  test  in 
the  manner  described.  If  it  be  demonstrated 
that  in  any  such  case  sugar  practically  exists 
in  the  urine,  in  never  so  small  a  quantity, 
dietetic  treatment  is  to  be  resorted  to,  until 
189 


SCHENICS    THEORY 

even  the  minutest  trace  of  sugar  has  been 
made  to  disappear. 

The  treatment  consists  in  giving  the  mother 
a  highly  nitrogenous  diet  with  fat,  and  add- 
ing only  so  much  carbo-hydrate  as  is  abso- 
lutely necessary  to  prevent  its  want  being 
felt. 

This  diet  should  be  continued  for  a  consid- 
erable time,  even  although  the  sugar  in  the 
urine  may  have  disappeared.  It  is  best  to 
begin  the  change  of  diet  a  good  while  (about 
2  or  3  months)  before  impregnation.  During 
the  menstruations  which  fall  within  this  pe- 
riod, the  ripened  ova  will  be  voided  unferti- 
lized, and  new  ova  which  have  been  influenced 
by  the  altered  conditions  of  nutrition  in  the 
organism  will  ripen  in  their  place. 

(If  we  follow  such  information  as  we  have 
concerning  the  development  of  sex  in  man, 
we  thence  conclude  that  the  difference  in  sex 
appears  at  the  beginning  of  the  third  month 
of  pregnancy,  and  is  definitely  expressed  in 
190 


THE   DETERMINATION  Of  SEX 

the  fourth  month.  From  this  it  would  appear 
not  to  be  superfluous  if  the  recommended 
alteration  of  diet  was  maintained  until  the 
beginning  of  the  third  month.) 

When  the  ovule  of  a  human  female,  dieted 
in  this  way,  becomes  fertilized,  it  has  been 
so  far  ripened  by  the  process  of  nutrition  con- 
ducted in  the  organism  of  the  mother,  that 
when  it  attains  the  stage  of  development,  it 
resolves  itself  into  cells  which  compose  an 
organism  containing  male  characteristics. 

After  impregnation  it  is  still  advantageous 
that  whilst  the  condition  of  the  urine  is  ex- 
amined at  intervals  of  a  few  days,  the  corre- 
sponding diet  should  be  continued  during  the 
advancing  stages  of  the  development. 

Although  I  do  not  here  take  the  trouble 
to  illustrate  these  diet  processes  by  explana- 
tions, every  one  can  have  regard  to  these 
particulars  for  himself,  and  conduct  the  diet 
even  after  impregnation  has  taken  place  in 
accordance  with  the  information  given  above. 
191 


SCHENK'S    THEORY 

In  a  case  like  that  mentioned,  where,  after 
marriage,  female  ova  were  successively  formed 
and  developed,  practically  a  process  of  physio- 
logical combustion  was  going  on  in  the  mother 
which  did  not  suffice  for  deriving  all  the  ad- 
vantage possible  from  the  food,  so  that  the 
available  elements  might  be  all  oxidized.  In 
consequence,  only  female  ova  were  fertilized 
and  only  female  individuals  born.  This  con- 
dition of  things  remained  the  same  for  a 
number  of  years. 

In  such  a  case  the  question  is  not  alone 
one  of  a  small  residuum  of  sugar,  but  in 
addition  to  this  it  is  probably  not  impossible 
that  other  substances  also  were  evacuated  from 
the  body,  to  make  use  of  which  was  not  within 
the  power  of  the  process  of  combustion. 

With  a  rational  diet,  these  substances  also 
might  be  withheld  from  evacuation  and,  as 
well  as  the  sugar,  be  made  available  for  com- 
bustion with  a  corresponding  increase  of  nour- 
ishment. 

192 


THE   DETERMINATION  OF  SEX 

In  experiments  of  this  kind  metabolic  ac- 
tivity will  show  itself  in  the  organism,  as  it 
may  be  perceived  from  the  nitrogenous  con- 
stituents of  the  urine  that  a  greater  exchange 
of  nutritive  matter  is  taking  place,  a  thing 
that  happens  also  with  normal  individuals. 

Under  these  circumstances  the  specific  grav- 
ity of  the  urine  is  also  increased,  and  it  may 
sometimes  become  relatively  considerable  (1030 
to  1035). 

In  consequence  of  the  influence  which  the 
altered  diet,  if  commenced  a  sufficiently  long 
time  before  conception,  exerts  both  over  the 
mother  and  over  the  ovum  which  is  being 
prepared  for  fertilization,  it  is  possible  that 
this  ovum  may  develop  itself  into  a  male  in- 
dividual. 

It  also  sometimes  happens  that,  even  with 
careful  dieting,  the  conditions  which  are  nec- 
essary for  our  purpose  are  not  realized  —  viz. : 
that  the  sugar  does  not  disappear  from  the 
urine,  that  the  mother  cannot  accommodate 

13  193 


SCffENJCS   THEORY 

herself  to  a  diet  of  the  kind  required.  She 
finds  the  situation  intolerable,  because  she 
cannot  do  without  an  abundance  of  starchy 
substances  and  sugar,  and  in  consequence  all 
hope  of  a  satisfactory  result  falls  to  the 
ground. 

There  are  persons  who  from  their  youth 
upwards  have  lived  principally  on  vegetable 
food,  and  are  therefore  not  accustomed  to 
take  the  nitrogenous  substances  of  their  diet 
in  the  concentrated  form  in  which  they  are 
presented  in  the  albuminous  constituent  of 
meat.  They  obtain  the  necessary  nitrogen 
for  the  body  from  large  amounts  of  food  con- 
taining a  great  quantity  of  water,  and  it  may 
happen  that  they  cannot  easily  submit  them- 
selves to  such  a  change  of  diet  without  per- 
nicious consequences.  To  this  class  belong 
the  women  who  live  in  the  rural  districts  of 
many  of  the  mountainous  regions  of  central 
Europe,  where  little  flesh  is  eaten.  With  them 
it  might  often  be  a  difficult  matter  to  make 
194 


THE   DETERMINATION  OF  SEX 

an  abrupt  change  of  diet  of  the  desired  kind. 
Such  individuals  can  be  reconciled  to  the 
kind  of  diet  we  recommend  only  by  a  gradual 
advance  in  the  quantity  of  concentrated  nitrog- 
enous food.  But  in  such  cases  it  might  very 
likely  prove  possible  to  attain  our  end  by  a 
corresponding  vegetable  diet. 


The  following  case,  which  was  conducted 
under  my  control  with  the  greatest  care,  and 
was  also  a  case  of  an  intelligent  woman, 
who  showed  the  greatest  willingness  to  do 
anything,  in  order  that  she  might  have  male 
offspring,  is  of  the  highest  interest  for  our 
theory. 

This  woman  was  of  a  family  in  wrhich  prin- 
cipally female  children  had  been  born.  Al- 
though all  its  members  were  fruitful,  no  great 
number  of  descendants  seemed  to  have  been 
reached.  It  is  not  unlikely  that  the  multi- 
plication of  descendants  was  restrained.  The 


SCHENK'S    THEORY 

existence  of  a  tendency  to  provide  female  ova 
for  fertilization  was  also  proved  by  testing  the 
urine  for  sugar. 

In  the  case  of  this  woman,  who  wished  to 
have  male  offspring,  the  examination  of  the 
urine  each  time  showed,  as  with  the  other 
women  of  the  family,  traces  of  sugar.  With 
her  ordinary  diet  sugar  was  found  in  the 
urine  (that  of  twenty-four  hours  being  col- 
lected) in  minute  quantities.  The  unoxidized 
minute  traces  of  sugar  signified  imperfect 
combustion. 

When  the  diet  is  to  be  altered,  it  is  neces- 
sary to  select  it  in  such  a  way  that  the  nitrog- 
enous substances  may  predominate  and  that 
the  carbo-hydrates  may  be  excluded  as  far  as 
possible.  Of  course  a  sufficient  quantity  of 
fat  must  be  added  to  the  food. 

The  food  to  be  taken  was  regulated  on  these 

principles,  and  the  dieting  began.    After  eight 

days  the  last  traces  of  sugar  in  the  urine  had 

disappeared.     The  woman's  health  was  good, 

196 


THE   DETERMINATION   OF  SEX 

and    she    at    once    showed    herself    contented 
with  the  highly  nitrogenous  diet. 

The  menses  lasted  five  days,  and  after  them, 
five  more  days  having  elapsed,  impregnation 
took  place,  the  same  diet  continuing.  After 
about  eight  weeks  of  pregnancy  the  food  was 
gradually  altered.  The  state  of  the  woman's 
health  during  pregnancy  presented  no  remark- 
able features.  She  had  taken  all  necessary 
care  of  herself,  and  her  condition  during  the 
pregnancy,  in  like  manner  as  before  it,  when 
she  had  to  alter  her  diet  until  the  sugar  dis- 
appeared from  the  urine,  was  satisfactory. 
She  was  in  due  course  confined  of  a  boy. 

A  year  and  a  half  passed.  The  woman 
bore,  after  similar  treatment  as  on  the  for- 
mer occasion,  a  second  boy.  In  the  interval 
no  further  control  was  exercised  over  her 
way  of  living,  but  a  few  weeks  before  she 
conceived  means  were  taken  to  regulate  her 
diet,  so  that  no  perceptible  trace  of  sugar 
resulted  from  its  physiological  combustion. 
197 


SCHENK'S    THEORY 

During  five  years  this  woman  did  not  con- 
ceive. The  results  of  examinations  of  the 
urine,  which  were  made  from  time  to  time, 
showed  quite  clearly  that  sugar  was  always 
normally  present.  The  quantity  was  not 
determined.  At  the  end  of  this  period  the 
woman,  after  a  long  rest,  and  a  similar  pre- 
liminary dieting,  once  more  became  pregnant. 
This  time  also  the  result  was  a  boy.  After 
two  years  another  boy  followed.  In  this  case 
also  a  similar  process  of  dieting  had  preceded. 

After  such  occurrences  it  was  sufficiently 
demonstrated  that  it  could  be  only  the  influ- 
ence of  the  diet  that  showed  itself  in  this 
way;  because  in  this  case  one  would  be  con- 
vinced that  it  was  not  a  mere  accident  that 
the  woman  here  spoken  of  produced  only 
male  offspring. 

In  the  case  of  this  woman  it  was  evidently 

•  the  diet  that  affected  the  development  of  sex, 

and  exerted  such  an  influence  that,  under  the 

improved  conditions,  the  metabolism  both  in 

198 


THE   DETERMINATION  OF  SEX 

the  mother  and  in  the  ripening  ovum  pre- 
paring for  fecundation,  took  such  a  form  that 
a  male  individual  was  developed. 

She  again  became  pregnant  after  a  lapse 
of  two  years.  Before  her  pregnancy  the 
same  system  of  diet  was  followed  as  on 
the  previous  occasions.  She  miscarried  in  the 
fifth  month.  Violent  emotions  and  mortifica- 
tions, accompanied  by  anxious  cares,  were, 
together  with  other  coincident  unfavorable 
circumstances,  the  cause  of  the  miscarriage. 
The  offspring  was  male. 

Soon  after,  some  four  months  after  the  mis- 
carriage, she  again  became  pregnant.  Also 
on  this  occasion  dieting  had  preceded,  such 
as  I  have  frequently  carried  out  for  the  de- 
velopment of  a  male  individual.  But  a  mis- 
carriage again  supervened.  The  foetus  was 
obviously  male. 

But  what  was  now  wanting  was  an  experi- 
ment that  could  be  added  to  the  preceding,  and 
199 


SCHENK'S    THEORY 

would  serve  to  show  that  a  human  female, 
who,  under  the  influence  of  our  method  of 
dieting,  invariably  bore  sons,  would,  in  the 
case  of  paying  no  attention  to  diet,  bring  a 
female  into  the  world. 

The  evidence  was  forthcoming,  for  the 
woman  in  question  again  became  pregnant 
without  any  consideration  being  bestowed  on 
her  bodily  condition,  and  without  anything 
being  done  to  remove  the  traces  ,of  sugar 


from  the  urine.  After  having  s^r€n  times 
borne  males  she  became  this  time  mother  of 
a  female,  which,  born  before  the  due  time, 
soon  died.  After  that  she  was  not  again 
pregnant.  Probably  some  change  supervened 
in  consequence  of  which  she  became  perma- 
nently unfruitful. 

This  incident  shows  sufficiently  that  the 
ovum  in  the  case  of  the  woman  who  served 
for  our  experiment  possessed  an  inherent 
tendency  to  develop  into  a  female,  and  was 

200 


THE   DETERMINATION  OF  SEX 

also  ripe  enough  to  be  fertilized.  As  we  had 
exercised  no  influence  upon  it  so  as  to  effect 
any  change  in  the  ovum  (in  the  same  way  as 
we  had  previously  been  able  to  affect  the 
others  by  the  diet  in  order  to  procure  the 
ovum  of  a  male)  the  result  was  a  female. 

The  female  tendency  was  therefore  already 
present  in  the  ovum,  and  indeed  the  mother 
supplied  convincing  evidence  of  the  female 
constitution  of  the  ovum  whilst  it  was  yet 
unfertilized,  because  sugar  existed  in  her 
urine.  The  previous  determination  of  the 
sex  could  also  in  this  case  present  no  diffi- 
culty. In  the  earlier  cases,  when  male  indi- 
viduals followed  one  another,  we  always 
aimed,  by  means  of  our  support  given  by 
means  of  the  nourishment  of  the  mother,  not 
only  at  the  ripening  of  the  ovum  which  was 
to  be  fertilized,  but  also  at  the  development  of 
a  male  individual.  In  the  last  case  the  ovum 
was,  without  any  assistance,  capable  of  being 
fertilized,  but  it  developed  into  a  female. 

201 


SCffEN/CS   THEORY 

A  ripe,  fertilizable  ovum  in  the  ovary  of  a 
woman  whose  urine  habitually  contains  sugar 
has  a  tendency,  when  the  proper  conditions 
are  supplied,  to  develop  into  a  female.  In 
consequence,  it  is  in  such  cases  from  the 
outset  possible,  without  exercising  any  influ- 
ence over  the  mother,  without  adopting  any 
diet,  to  anticipate  after  a  conception,  the 
birth  of  a  female  individual.  But  if  these 
conditions  do  not  exist,  if  no  sugar  can  be 
detected  in  the  urine,  the  use  of  the  same 
influence  in  order  to  obtain  a  male  individual 
is  still  not  superfluous.  In  this  case  also 
there  is  a  need  of  an  alteration  of  diet, 
although  the  individual  in  question  accom- 
plishes the  process  of  physiological  combustion 
in  a  manner  which  must  be  called  the  most 
favorable  possible,  seeing  that  with  a  mixed 
diet  all  the  oxidizable  materials  are  com- 
pletely used  up. 

Supposing  that  a  mother  of  this  sort  wished 
for  female  offspring,  one  would  not  be  in  a 

202 


THE   DETERMINATION   OF  SEX 

position  to  give  any  advice.  In  this  case  one 
cannot,  according  to  the  facts  which  have 
been  mentioned  above,  exercise  any  influence 
over  an  alteration  in  the  course  of  the  develop- 
ment of  the  ovum  which  would  occasion  the 
birth  of  a  female.  Such  a  mother  is,  up  to 
the  present  time,  beyond  the  reach  of  an 
influence  that  can  affect  the  development  of 
the  future  sex. 


Two  other  cases  follow  in  which  male  chil- 
dren were  desired,  several  females  having  so 
far  been  the  offspring  of  the  marriage.  The 
corresponding  arrangements  for  the  regula- 
tion of  the  diet,  which  led  to  the  complete 
disappearance  of  sugar  from  the  urine,  showed 
themselves  effective  in  the  ripening  of  the 
ovum,  and,  after  conception  had  taken  place, 
in  both  cases  a  male  individual  was  formed 
and  developed. 

In  addition  to  this,  four  other  cases  were 
under  observation,  in  which  no  influence  was 
203 


SCHENK'S    THEORY 

exercised  on  sugar  occurring  in  the  urine  in 
quantities,  such  as  correspond  to  a  normal 
healthy  state.  Without  any  kind  of  influence 
of  diet,  three  females  were  born. 

In  a  fourth  case  I  had  a  negative  result. 
In  three  cases  the  result  was  positive.  In 
the  last  three  cases  I  was  able  to  examine 
the  urine  as  often  as  I  wished,  whilst  in  one 
case  I  was  allowed  to  do  so  only  at  long 
intervals  as  a  favor. 


Let  us  now  in  conclusion  endeavor  to  make 
some  short  reflections  on  the  results  which 
we  are  able  to  attain. 

First  of  all  one  would  say  that  in  certain 
regions  and  among  certain  peoples,  where 
meat  forms  the  principal  diet,  only  male,  or 
principally  male,  offspring  would  be  antici- 
pated. 

The  nutrition  of  the  mother  certainly  plays 
a  leading  part  in  the  development  of  the 
204 


THE   DETERMINATION   OF  SEX 

ovum  within  her  body.  The  different  ex- 
periments which  breeders  have  made,  and 
the  observations  which  have  repeatedly  shown 
in  the  case  of  the  invertebrata  (v.  Berlepsch, 
( Die  Biene  und  ihre  Zucht?  second  edition; 
Landois,  *  Physiologic*),  a  connection  between 
food  and  the  development  of  sex  leave  no 
doubt  that,  in  the  case  of  the  human  subject 
also,  a  certain  diet  of  the  mother  would  not 
be  without  influence  on  the  ovum  developing 
within  her.  Here,  however,  in  the  case  of 
the  ripening  of  the  ovum,  according  to  my 
opinion,  the  result  does  not  depend  on  the 
diet  alone,  but  rather  on  the  process  of 
metabolism  in  the  mother. 

How  the  physiological  combustion  goes  on 
in  the  organism,  and  what  changes  take  place 
in  it,  in  consequence  of  the  altered  diet, 
until  the  sugar  entirely  disappears,  is  in  the 
case  of  human  beings  of  the  highest  im- 
portance, and  furnishes  an  index  of  the  con- 
sequences. 

205 


SCHENK'S    THEORY 

In  individual  cases  the  diet  is  directed  in 
accordance  with  the  results  that  show  how 
the  food  has  been  assimilated  and  does  not 
depend  upon  these  alone.  In  other  words, 
whether  the  mother  eats  much  meat  is  a  sec- 
ondary consideration.  Whether  and  how  the 
food  taken  is  completely  made  use  of  in  the 
process  of  combustion  —  that  is  a  matter  of 
importance  for  the  purpose  we  have  in  view. 

Any  one,  who  keeps  before  him  the  funda- 
mental principles  of  this  theory,  will  see 
plainly  that  it  is  possible,  under  certain  cir- 
cumstances, to  procure  male  progeny  by 
means  of  the  influence  we  have  indicated. 
The  wish  to  have  female  progeny  is  a  desire 
for  the  gratification  of  which  it  is  not  at 
present  possible  to  give  any  directions. 


In  connection  with  all  that  I  have  already 
said   I    will    here    mention    that    the    method 
which  I  employed  to  procure  the  ripening  of 
206 


THE   DETERMINATION  OF  SEX 

an  ovum  for  male  progeny  in  cases  where  I 
had  previously  found  sugar  normally  present, 
which  served  as  an  indication  for  the  applica- 
tion of  my  treatment,  I  attempted  to  apply 
also  in  the  case  of  individuals  with  whom  no 
trace  of  sugar  was  to  be  found.  The  method 
of  proceeding,  judging  by  my  experiences 
thus  far,  should  be  as  follows. 

First  of  all,  it  must  be  elicited  whether  any 
special  disease  exists,  and  especially  any  that 
indicates  anomalies  in  the  metabolism.  Of 
course  capacity  for  generation  and  the  possi- 
bility of  conception  are  presupposed. 

If  the  history  of  the  case  shows  no  circum- 
stances that  would  hinder  the  application  of 
the  method,  we  inform  the  patient  that  she 
must  furnish  us  with  the  urine  necessary  for 
the  occasional  examination.  It  is  best  to  use 
for  this  purpose  a  urine  glass  marked  in 
grammes  and  containing  two  litres,  in  which 
the  urine  of  twenty-four  hours  is  to  be  col- 
lected. 

207 


SCHENK'S    THEORY 

It  is  well  at  the  beginning  of  the  proced- 
ure to  put  a  few  drops  of  formaline  into  the 
measuring-glass,  so  that  the  urine  may  not, 
in  consequence  of  standing,  decompose,  and 
so  become  unfit  for  accurate  analysis.  Of  the 
collected  quantity  of  twenty-four  hours,  about 
200  grammes  should  be  poured  into  a  small 
phial,  well  corked,  and  used  for  analysis.  In 
making  the  analysis  it  is  best  to  proceed  in 
the  following  order:  First,  we  determine  the 
reaction  of  the  urine  with  litmus  paper.  In 
normal  urine  the  reaction  is  generally  acid. 
Next  the  specific  gravity  is  determined.  This 
is  most  easily  done  with  Ultzmann's  uro- 
meter,  by  means  of  which  the  density  of 
the  urine  can  be  easily  determined.  That 
varies  in  normal  urine  generally  between  1015 
and  1020.  In  exceptional  cases  it  may  sink 
very  low,  which  often  happens  after  much 
fluid  has  been  taken.  In  other  cases  it  rises 
under  pathological  circumstances  enormously 
high,  as,  for  example,  in  diabetes.  In  the 

208 


THE   DETERMINATION  OF  SEX 

case  of  a  thorough  preparation  of  the  organ- 
ism by  the  use  of  a  great  quantity  of  con- 
centrated nitrogenous  food  with  a  view  to 
influencing  sex,  the  specific  gravity  very 
often  reaches  1030  and  more. 

After  the  specific  gravity  we  measure  next 
the  quantity  of  urine  collected  in  the  twenty- 
four  hours. 


We  proceed  next  to  determine  the  normal 
urine-sugar,  and  for  this  purpose  use  a  num- 
ber of  the  well-known  tests — Nylander's,  the 
fermentation  test,  and  Trommer's  test — which 
have  been  already  described.  If  these  give  a 
positive  result,  we  proceed  to  a  quantitative 
examination  by  means  of  the  polariscope.  If 
the  quantity  of  sugar  found  is  very  small, 
we  exert  ourselves  to  get  rid  of  it  by  a  suit- 
able diet,  because  otherwise  no  certain  influ- 
ence over  the  embryo  in  the  direction  of  the 
production  of  male  offspring  can  be  exercised. 
If,  however,  we  find  no  sugar  by  any  of  the 

14  209 


SCHENK'S    THEORY 

above  tests,  we  seek  for  it  by  means  of  the 
phenylhydrazin  test  also  described  above.  A 
few  experiments  on  the  melting  point  of  the 
phenyl-glycosazon  crystals  will  easily  give  us 
certain  information.  In  the  analysis  we  ob- 
serve particularly  whether  the  positive  result 
of  the  phenylhydrazin  test  has  originated 
from  the  sugar  or  from  the  reducing  sub- 
stances. With  the  polarization  apparatus  we 
determine  the  quantity  of  laevo-rotatory  sub- 
stances, the  optical  rotation,  in  per  cents.,  as 
these  stand  in  a  certain  relation  to  the  reduc- 
ing substances.  We  make  these  experiments 
with  urine  that  has  not  been  decolorized. 
The  former  becomes  greater  as  the  quantity 
of  the  latter  increases. 


The  determination  of  the  reducing  substances 
can  be  effected  by  Salkovski's  gravimetric 
method,  but  I  prefer  Moritz's  volumetric 
method,  on  account  of  its  simplicity.  For 


THE   DETERMINATION  OF  SEX 

the  experiment  we  prepare  the  following  so- 
lutions: i.  A  solution  of  sulphate  of  copper 
of  80.78  grammes  Cu  S  O4  +  5  H2  O,  in  a 
litre;  2.  Solution  of  caustic  soda  of  120 
grammes  Na  H  O,  in  a  litre;  3.  Watery  so- 
lution of  ammonia,  of  7.1  per  cent.  N  H3, 
specific  gravity  0.9722.  For  conducting  the 
volumetric  analysis  we  place  in  one  of  Erlen- 
mayer's  flasks,  containing  about  250  cubic 
centimetres,  about  2  cubic  centimetres  each 
of  the  soda  solution  and  the  solution  of  sul- 
phate of  copper,  and  add  140  cubic  centime- 
tres of  the  ammonia  solution.  We  thus  obtain 
a  dark  blue  fluid,  which  we  now  boil.  Dur- 
ing the  boiling  we  allow  the  urine  to  be  an- 
alyzed to  flow  in  from  a  burette  until  the 
fluid  becomes  colorless.  A  table  given  by 
Moritz  in  the  forty-sixth  volume  of  the  *Ar- 
chiv  fur  klinische  Medizin?  shows  us  in  per 
cents,  the  quantity  of  reducing  substances  con- 
tained in  the  urine  we  have  used. 

In  conclusion  we   investigate  the  condition 

211 


SCHENK'S    THEORY 

of  metabolism  by  determining  the  excreted 
nitrogen.  Nitrogen  is  excreted  both  by  the 
urine  and  the  faeces.  The  greater  part  is 
found  in  the  urine,  whilst,  on  the  contrary,  the 
quantity  of  nitrogen  excreted  in  the  faeces 
amounts  to  more  than  i  gramme  per  day. 
If,  then,  we  determine  the  quantity  in  the 
urine  alone  and  add  0.94  gramme  as  a  cor- 
rection for  the  nitrogen  excreted  with  the 
faeces,  the  resulting  error  will  be  unimpor- 
tant. The  best  and  at  present  most  useful 
method  of  determining  the  nitrogen  is  that 
of  Kjeldahl.  I  generally  use  it  in  my  analy- 
ses as  one  that  can  be  conveniently  carried 
out.  For  this  purpose  we  place  5  cubic  cen- 
timetres of  filtered  urine  in  a  long-necked 
flask,  add  about  3  decigrammes  of  yellow  ox- 
ide of  mercury  and  10  cubic  centimetres  of 
chemically  pure  sulphuric  acid.  We  then 
carefully  warm  the  brownish-black  mixture 
over  the  flame  of  a  Bunsen  burner  until  it 
has  become  colorless.  We  now  allow  it  to 

212 


THE  DETERMINATION  OF  SEX 

cool.  The  mixture  is  now  poured  into  an 
Erlenmayer  flask  containing  three-quarters  of 
a  litre  of  water,  is  neutralized  with  30  per 
cent,  soda-lye,  and  then  40  cubic  centimetres 
of  a  4  per  cent,  solution  of  potassium  sul- 
phide is  added.  The  whole  is  next  subjected 
to  distillation.  Decinormal  sulphuric  acid 
contained  in  the  receiver  takes  up  the  am- 
monia which  distils  over.  The  acid  still 
remaining  free  after  the  completion  of  the 
distillation  is  titrated  with  decinormal  caus- 
tic soda.  As  i  cubic  centimetre  of  decinor- 
mal sulphuric  acid  corresponds  to  0.0014 
gramme  of  nitrogen,  we  can  easily  reckon 
the  quantity  excreted  daily.  We  know  how 
much  nitrogen  is  contained  in  5  cubic  centi- 
metres of  urine,  and  can  easily  find  to  how 
much  the  daily  quantity  amounts  by  multi- 
plying by  it  and  dividing  by  five. 

The    nitrogen   found   in   the   urine   can  be 
expressed   as   albumen    by   multiplying  it   by 
6.25  (Neumeister),  at  the  same  time  making 
213 


SCHENICS   THEORY 

a  correction  for  the  nitrogen  in  the  faeces  as 
described  above. 

This  is  all  that  there  is  to  say  about  the  anal- 
ysis of  the  urine,  which  is  of  so  much  impor- 
tance for  our  experiments.  In  order  to  show 
the  practical  application,  I  will  add  the  fol- 
lowing analyses,  as  actually  made  in  exer- 
cising an  influence  over  sex  to  obtain  male 
offspring. 

i.  Case  of  a  woman  twenty-three  years 
old,  who,  before  anything  was  done  to  influ- 
ence the  sex  of  her  offspring,  had  been  mar- 
ried five  years,  and  had  given  birth  to  two 
girls.  The  urine  was  collected  from  eight  in 
the  morning  until  the  same  hour  of  the  next 
day  in  a  measuring-glass.  The  quantity  in 
twenty-four  hours  was  1,650  cubic  centimetres. 
Analysis  gave  the  following  results  :  — 

ANALYSIS. 
Reaction:  Acid. 
Specific  gravity :  1017. 

214 


THE   DETERMINATION  OF  SEX 

Quantity  in  24.  hours:  1650. 
Color:  Light  yellow,  fairly  pale. 
Sugar :  None  perceptible  with  Trommer's 
test,    the    fermentation    test,    and    Ny- 
lander's  test. 

Phenylhydrazin  test:  Negative. 
Optical    rotation :    Very    slight,    not    de- 

terminable. 

Reducing  substances :  0.135  Per  cent. 
Nitrogen  :   12.76  (Correction  o.  94) . 
Nitrogen  as  albumen:  79.75. 
I  recommended  that  more  meat  should  be 
taken,  and    that    sugar    and    other    forms   of 
carbo-hydrate  should  be  avoided.      After  the 
lapse  of   eight  days,   I  again   procured  urine 
for  examination.    Analysis  gave  the  following 
results  :  — 

ANALYSIS. 
Reaction :  Acid. 
Specific  gravity  :   1018. 
Quantity  in  24.  hours:   1050. 

215 


SCHENK'S    THEORY 

Color:  Somewhat  darker  than  on  17,   i. 

Sugar :  None  perceptible  with  Trommer's 
test,  the  fermentation  test,  and  Ny- 
lander's  test. 

Pkenylhydrazin  test:  Negative. 

Optical  rotation :  Not  determinable. 

Reducing  substances :  0.15  per  cent. 

Nitrogen:  13.5  (Correction:  0.94). 

Nitrogen  as  albumen:  84.37. 
The  result  was  that  the  reducing  sub- 
stances and  the  nitrogen  (expressed  as  albu- 
men) had  increased.  The  diet  of  this  woman 
was  constantly  altered  in  the  direction  of 
increasing  the  amount  of  albumen,  until,  after 
the  lapse  of  about  three  weeks,  the  following 
results  were  obtained  :  — 

ANALYSIS. 

Reaction:  Acid. 
Specific  gravity :  1030. 
Quantity  in  24.  hours:  1000. 
Color:  Dark,  brownish-yellow. 

216 


THE   DETERMINATION  OF  SEX 

Sugar :  Cannot  be  determined  by  Trom- 
mer's  test,  the  fermentation  test,  and 
Nylander's  test. 

Pkenylhydrazin  test:  Positive;  the  glyco- 

sazon-crystals  have   melting-point    no0 

Cent.,  therefore  do  not  result  from  sugar. 

Optical  rotation :    o.  2   per    cent,  laevo-ro- 

tatory. 

Reducing  substances :  0.32  per  cent. 
Nitrogen :    21.9    grammes    (Correction  :  i 

gramme). 

Nitrogen  as  albumen:  136.8  grammes. 
The  woman  was  kept  in  this  condition  four 
weeks.  In  the  meantime  menstruation  took 
place.  It  lasted  four  days,  during  which  time 
no  change  appeared  in  the  analysis.  An  analy- 
sis was  made  every  week.  Another  menstrua- 
tion occurred,  lasting  four  days,  and  impreg- 
nation took  place  six  days  later.  After  this 
the  menses  ceased.  As  I  mentioned  above, 
the  sex  of  the  embryo  is  already  determined 
in  the  third  month  of  pregnancy,  for  which 

217 


SCHENK'S   THEORY 

reason  I  kept  the  patient  under  dietary  in- 
fluence up  to  that  time.  In  the  interim  I 
made  ten  analyses  at  short  intervals,  the  aver- 
age results  of  which  I  shall  now  give. 

AVERAGE  of  TEN  ANALYSES. 

Reaction :  Acid. 

Specific  gravity :  1028-1032. 

Quantity  in  24.  hours:  750  cubic  centi- 
metres, to  1 200. 

Color:  Golden  yellow,  always  dark. 

Sugar :  None  could  ever  be  detected. 

Phenylhydrazin  test:  Positive  (owing  to 
the  presence  of  glycuronic  acid  com- 
pounds; melting-point  of  crystals  105° 
cent,  to  120°). 

Optical  rotation :  o.  2-0. 3  per  cent,  laevo- 
rotatory. 

Reducing  substances :  0.29-0.35  per  cent. 

Nitrogen:  17.9  grammes  to  22  grammes 
(Correction  i  gramme). 

Nitrogen  as albu men :  111.8-137.5  grammes. 
218 


THE   DETERMINATION   OF  SEX 

When  after  5  analyses  the  nitrogen  (ex- 
pressed as  albumen)  had  reached  its  highest 
point,  it  fell  suddenly.  Some  immediate  ex- 
periments proved  that  it  was  necessary  to 
give  more  carbo-hydrates  and  less  albuminous 
food,  in  order  to  re-establish  the  previous  re- 
lations. 

The  woman  was  subsequently  allowed  to 
follow  whatever  course  she  preferred,  and 
bore  a  fine  boy  at  full  term. 

The  task  still  remains  of  examining  many 
facts  and  theories  already  known  which 
may  apparently  be  contradictory  to  our 
teaching. 

And  here  should  be  first  of  all  taken  into 
consideration  the  experiments  in  diet  made 
by  various  stockbreeders  (Bellingers,  Wilkens, 
etc.).  In  them,  however,  the  results  of  the 
analysis  of  the  products  of  excretion  are  not 
given,  and  in  particular  there  is  no  information 
respecting  the  combustible  and  useable  sugar 
evacuated  from  the  organism,  or  any  other 
219 


SCHENJCS    THEORY 

substances  from  the  organism  which  might 
have  been  of  importance  for  the  evaluation 
of  the  food.  It  is  possible  that  in  experi- 
ments with  diet,  without  reference  to  the 
excretion  of  sugar,  the  results  may  be  some- 
times in  favor  of  the  male  and  sometimes 
in  favor  of  the  female  sex,  upon  which  latter 
no  active  influence  is  exercised.  Herr  U.  P., 
a  nobleman  resident  in  a  country  district  of 
the  Russian  Baltic  provinces,  informed  me  by 
letter  that  in  his  herds  the  greater  number 
of  calves  are  born  in  February.  The  Febru- 
ary calves  are  principally  male.  The  cause 
in  this  case  may  be  as  follows:  —  Conception 
takes  place  in  the  May  of  the  previous  year. 
After  having  been  kept  some  six  months  in 
the  cow-houses,  the  beasts  are  turned  into 
the  spring  meadows,  and  are  impregnated  at 
a  period  when  metabolism  is  active  in  conse- 
quence of  their  altered  mode  of  life.  All  the 
cows  are  in  heat.  The  notable  result  ob- 
tained in  the  ensuing  February  may  be 


220 


THE   DETERMINATION  OF  SEX 

explained  as  the  consequence  of  the  better 
physiological  combustion  of  the  food. 

According  to  statistics  more  boys  than 
girls  are  born  in  the  years  with  a  poor  har- 
vest. Bad  harvest  years  are  those  which 
favor  a  flesh  diet,  as  the  food-stuffs  from  the 
vegetable  kingdom  do  not  suffice  for  the  cat- 
tle, nor  for  the  people  either;  in  consequence 
of  which  the  cattle  are  killed,  and  more  flesh 
enters  into  the  diet  of  the  women  who  are 
fructified.  If  people  in  general  had  the  nor- 
mal aptness  for  procreation  in  such  famine 
years,  the  flesh-diet  might  turn  the  scale  in 
favor  of  the  male  sex;  it  being  presupposed 
that  the  other  conditions  were  fulfilled. 

If  Thury's  law  be  considered,  Thury  also 
held  the  ripeness  of  the  ovum  to  be  of  im- 
portance for  male  or  female  ova.  The  ova 
were  regarded  by  this  author,  as  being  more 
or  less  ripe,  or  as  male  and  female,  accord- 
ing to  the  time,  whether  it  happened  to  be 
at  the  beginning  or  at  the  end  of  the  rut- 

221 


SCHENK'S    THEORY 

ting.  To  me,  however,  the  ripeness  seems 
to  depend  upon  the  process  of  physiological 
combustion  in  the  organism  of  the  mother. 
According  to  Thury  no  attention  need  be 
paid  by  us  to  the  ripeness  for  fructification, 
as  this  ripeness  is  attained  independently  of 
our  interference.  But,  on  the  other  hand,  our 
influence  has  the  effect  of  producing  a  male 
ovum  out  of  the  ovule  ready  to  be  fructified. 
If  the  dieting  of  a  woman  in  the  way  we 
recommend  is  practicable  and  of  definite 
effect  upon  the  development  of  the  future 
sex,  we  arrive  at  a  conclusion  which  may  be 
summed  up  as  follows  :  —  If  a  woman  be 
dieted  according  to  our  method,  she  can 
reach  a  stage  in  which  she  becomes  sexually 
superior  to  the  man,  and  her  offspring  will 
then  be  male,  in  accordance  with  the  law  of 
the  cross-heredity  of  sex. 


222 


DATE    DUE    SLIP 

UNIVERSITY  OF  CALIFORNIA  MEDICAL  SCHOOL  LIBRARY 


THIS  BOOK  IS  DUE   ON  THE   LAST  DATE 
STAMPED  BELOW 


FEE  C     101 


2m-12,'19 


"1 


6chenk,L 


7102 


ihenk  '  s   theory  : 


no  t.i  nr 


of   sex 


6      T93T  FEB  1 1    193' 


y 


Unlyetsity  of  CaOifornia  Medical  School  LiDraty 


